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Search form, you are here, automated firearms ballistics technology.

As with fingerprints, every firearm has unique characteristics. The barrel of a weapon leaves distinct markings on a projectile. The breech mechanism also leaves distinct markings on the cartridge case. These markings are produced by the breech face itself, the firing pin, extractor, and ejector. Firearms examiners are able to examine bullets and cartridge casings to determine if they were expelled from the same firearm. It has been a tedious, time-consuming process for firearms examiners to compare suspect bullets and cartridge casings recovered at crime scenes or from a recovered firearm to the vast inventory of recovered or test-fired projectiles and casings. The severe stress and eye strain on the firearms examiner slow the process. Therefore, realizing that the present examination techniques were antiquated, ATF and the Department of Treasury recognized the potential benefits to law enforcement that innovative computerized, crime-fighting technology can provide. This investment is currently being utilized as an information super highway in the solving of firearms-related violent crimes by ATF and participating law enforcement agencies. Since January 2004, ATF is under the United States Department of Justice.

Ballistic Comparison System

Currently, ATF is utilizing a unique ballistic comparison system that allows technicians to digitize and automatically sort bullet and shell casing signatures and aids in providing matches at a greatly accelerated rate. The equipment expeditiously provides investigators with leads to solve greater numbers of crimes in a shorter period of time.

The Integrated Ballistic Identification System (IBIS) provides a single system capable of comparing both types of ballistic evidence found at crime scenes. This integrated and automated imaging system permits a technician to enter and review large numbers of fired bullets and expended cartridge cases and cross reference hits made from each system for examination by a firearms examiner. Statistics collected by ATF’s National Tracing Center (NTC) indicate that revolvers and semiautomatic firearms are traced with nearly equal frequency by law enforcement agencies.

The ballistic comparison of crime scene bullet or cartridge casing evidence can be automatically compared with other bullet or cartridge casing images previously entered into the system. The ballistic comparison system does not positively identify (match) bullets or casings fired from the same weapon — that must be done by a firearms examiner. However, the system does produce a short list of candidates for the match. The numerical probability of a match is given for each candidate on the list eliminating the need for the examiner to visually compare unlikely candidates. By doing automated searches, the system speeds up and optimizes time spent on comparisons. The best evidence in linking a firearm to a specific crime is matching the recovered projectile and cartridge casings to the suspect firearm.

The IBIS consists of two separate work stations — a Data Acquisition Station and an Image Analysis Station. These stations operate in an independent manner. The Data Acquisition Station is used to collect image data. It does not retrieve and compare images. Laser optics focus on the bullet’s land markings, and a computer digitally maps and records the significant areas on the bullet’s surface. These areas are selected and optically “marked” by the technician as the bullet is viewed while being rotated. Shell casings are much simpler to acquire requiring no manipulation of the specimen. Either a firearms examiner or a technician can be trained to enter data from crime scene bullets and casings.

The system is designed to be operated by a technician with no previous computer experience. The firearms examiner’s only contact with the system can be after all the data has been entered and correlated. At this point, the firearms examiner will review the scores and view only those with significant scores at the Signature Analysis Station (SAS). The SAS runs the image comparison software, and it houses the data base of images generated by the Data Acquisition Station. One analysis station can handle the data from several acquisition stations. Data can be manually transported and entered into the analysis station from a disk or electronically transported through a communication line.

As stated earlier, the system does not make identifications; the firearms examiner must make the identification if two bullets or cartridge cases come from the same firearm. Since, the system produces a list of scores that indicate the relative and quantitative probability of a match (high to low), the firearms examiner can retrieve selected images for evaluation on the video screen. If the image on the screen looks as though a match could exist, the firearms examiner inspects the specimens on a comparison microscope to confirm the match. Recently ATF purchased the newest technology, IBIS BrassTrRAX. The new IBIS BrassTRAX Systems will help ATF move NIBIN into a new era of crime fighting. Utilizing IBIS technology, BrassTRAX is a highly-automated desktop acquisition station that collects images of fired cartridge cases and forwards them to be searched against the NIBIN Database.

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'Smart gun' innovators seek to reduce firearm deaths

Olivia Hampton

technology and firearm evidence presentation

The LS9, a "smart gun" being developed by LodeStar Works, can be locked or unlocked through three security mechanisms: the owner's thumbprint, a Bluetooth-enabled app and a PIN pad. The little dark square near the yellow sticker on the guns shown here is where the owner's thumb would unlock the gun. Ginger Chandler hide caption

The LS9, a "smart gun" being developed by LodeStar Works, can be locked or unlocked through three security mechanisms: the owner's thumbprint, a Bluetooth-enabled app and a PIN pad. The little dark square near the yellow sticker on the guns shown here is where the owner's thumb would unlock the gun.

Ginger Chandler had a hunch. She'd spent years developing products for major gun manufacturers Smith & Wesson and Remington, so gun safety was a big topic at home. But when her stepfather passed away, she worried that her own gun-savvy mom didn't store his gun properly — the type of common mistake that causes scores of accidental deaths in the U.S. each year. When they went to check on the gun, there it sat in an unlocked drawer with the ammo next to it.

"I said, 'Mom, we talk about this all the time. If you didn't know, there are so many people who don't know,'" Chandler recalled.

This anecdote is part of what motivated Chandler to join the startup LodeStar Works as it develops a "smart gun" that features three options so that it can be unlocked only by its registered owner. This type of technology could help prevent accidental firearm deaths, suicides or homicides by unauthorized users. But it's not gun control, and it also would not prevent a mass shooting perpetrated by someone who legally purchased the weapon used.

"In the United States, there are a lot of firearms out there, and people are just unaware that their own firearms aren't safe. Everybody's kind of going, 'Oh, that guy's stuff is not safe but mine's good,'" Chandler said.

The LS9, a 9 mm pistol that Chandler and her team hope to bring to market next year, uses biometrics so that the owner's thumbprint can unlock the weapon, as well as a PIN pad and a Bluetooth connection that works with a mobile app.

It’s the heart of the LodeStar Works Firearm that sets it apart. This ‘Locking Mechanism’ will change the way you carry! Learn more at #personalizedcarry #edc — LodeStar Works (@LodestarWorks) June 20, 2022

Gun violence is one of the most confounding and intractable problems in the United States. Every day, over 100 people die from gunshots — part of the more than 300 individuals who are shot each day, according to the Brady Campaign to Prevent Gun Violence . But the right to own guns is enshrined in the U.S. Constitution, and the issue has torn at America's social fabric.

While not explicitly opposed to smart guns, the National Rifle Association has raised concerns that if these firearms become commercially viable, the technology could become mandatory for all guns sold in the United States. In fact, President Biden's own campaign platform called for all firearms sold nationwide to be smart guns. And a recent NPR/Ipsos survey found that most American gun owners support moderate gun control measures such as background checks or increased age requirements.

But the last time a smart gun was available in the U.S., it failed miserably. In 2014, hackers broke into the radio-frequency identification (RFID) of German manufacturer Armatix's product, and magnets could also disable the locking mechanism.

Chandler is determined to get it right this time. At the next level of testing, when the prototypes will be tooled up, LodeStar Works plans to enroll the help of hackers to identify any potential weaknesses and resolve them. Additionally, the profile of the typical gun buyer has changed significantly , which could help improve the viability of a product like the LS9 on the market. Last year, in the midst of the COVID-19 pandemic, about half of new gun owners were women, and nearly half were people of color.

"They want to own their own destiny. But they also have small children at home. ... Maybe they're working remotely with their older children," Chandler explained. "They don't want to just have firearms out, but they also want to be in control."

LodeStar Works uses #bluetooth tech to connect to its personalized firearm. #BelieveItOrNot it’s happening #righthererightnow — LodeStar Works (@LodestarWorks) April 20, 2022

Margot Hirsch has provided support to innovators like Chandler through her Smart Tech Challenges Foundation for the better part of a decade. In 2014, the foundation provided a total of $1 million in grants to 15 gun safety innovators.

"Breaking ground in a very traditional industry continues to be hard," Hirsch said. "The firearm industry is not one to innovate. My sense is they'll only do it when they're forced to do it. And so it takes really brave innovators to forge a path in this area."

Firearm-related injuries are now the leading cause of death among children and adolescents from age 1 to 19, according to expert analysis of data from the Centers for Disease Control and Prevention. And that's where Hirsch says smart guns could play an important role in reducing deaths.

"Mass shootings, as horrific as they are — and they obviously dominate the news — they account for less than 2% of the injuries and deaths due to guns," she said. "Although a smart gun might not prevent a mass shooting, they could definitely be used to address youth suicides."

At the same time, it's unlikely that traditional guns would get traded in for smart guns, which aren't even sold yet.

"We do believe that gun owners, when they go to buy new guns, will consider these guns for multiple reasons, and one is for personal protection," Hirsch explained. "This could be the gun that is readily available, let's say, on the bedside table, in the kitchen, wherever, where it's secured and locked and their children can't access it. But they know that if someone broke in their house or tried to take their weapon from them, it could not be used in that type of scenario."

Anti-gun violence activists note that introducing smart guns is also adding to the number of weapons available, but Hirsch stresses that firearms are going to remain available "for the foreseeable future."

"So, if people are going to continue to buy guns, we believe it is imperative that there is a smart gun option on the market. I do think it's imminent," she said.

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  • Firearms History and the Technology of Gun Violence
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This online exhibit was designed to provide context for the 2019-20 Campus Community Book Project topic of gun violence as the UC Davis community reads and discusses  Another Day in the Death of America: A Chronicle of Ten Short Lives , by Gary Younge.

It complements the exhibit, Gun Violence in America , that was on display at Shields Library during October 2019 and a related talk by librarian Matt Conner.

The online exhibit provides a historical perspective on the development of modern firearms, based on the belief that, to understand gun violence, one must understand something about guns.

The First Modern War

The American Civil War (1861-1864), which transformed American history, also changed the history of warfare. It has been called the First Modern War. The reason for this label can be seen in two images from the beginning and end of the war.

technology and firearm evidence presentation

The First Battle of Bull Run (July 21, 1861), pictured here, was the first major battle of the war, and it convinced all sides that they were not going to win with a quick victory but were in for a major conflict. With the close-packed formations of men using volleys of rifle fire, the scene would not have been out of place in the Revolutionary War, 70 years earlier. But only a few short years later, at the siege of Petersburg, VA, (June 15, 1864 to April 2, 1865), which led directly to the surrender of Robert E. Lee and the end of the Confederacy, the scene changed completely.

technology and firearm evidence presentation

The empty battlefield of modern warfare had emerged, where no one is visible because they have taken cover behind fortifications. This scene resembles the trenches of WWI, 70 years later, in which European armies relearned the lessons of the Civil War at terrible cost. Another feature of the first modern war is  the use of all categories of modern weapons, including armored warships, submarines, machine guns and repeating rifles. It even featured aerial warfare in the form of observation balloons. Yet, the radical transformation in tactics did not result from these exotic technologies but from the humble muzzle-loading longarm with one critical difference from the Revolutionary War.

Rifled Bore

The standard rifle of the Union Army of the Civil War was the 1861 Springfield Rifled Musket.

technology and firearm evidence presentation

The Confederates used a similar weapon, the Pattern 1853 Enfield Rifled Musket imported from Britain. The Springfield rifle differed in two respects, one major and one minor, from Revolutionary War muskets. The minor difference was the percussion ignition system. Revolutionary muskets had used a flintlock system whereby a flint was moved by a trigger mechanism to strike against a metal surface to generate a spark to ignite the gunpowder. The Springfield used a hammer to strike a metal “cap” to generate the spark. The new system was more enclosed and efficient, but fundamentally similar. The major difference was the use of a rifled bore. Whereas musket barrels were smooth tubes, a rifled bore had spiral grooves running the length of the barrel. Anyone who has seen a James Bond movie has seen rifling.

technology and firearm evidence presentation

The ’70s themed funky spirals are rifling grooves seen from the viewpoint of a bullet pointed at James Bond. By engraving the soft lead of the bullet in its passage, the rifling imparts spin, which enabled far greater range and accuracy. Where smooth-bore muskets were accurate to less than 100 yards and needed to be fired in volleys to have any effect, the new rifles could hit man-sized targets out to 800 yards. It was this innovation which swept battlefields clean. With such range, it became suicidal to use the massed formations of earlier time, and hiding behind cover was the only option.

Interrelated Advances

The success of the rifled musket laid the groundwork for future advances. For all its achievements, the rifled musket had glaring problems — two in particular. The first was a very complex loading process. The cartridge of the time consisted of a measure of gunpowder and a bullet contained in a paper packet. To load, the soldier tore the packet with his teeth and emptied the gunpowder down the muzzle. He then dropped the bullet after it. Finally, he wadded up the paper and, with the aid of a ramrod, packed everything into place at the other end of the barrel. Then, he reversed the rifle to take his shot. This complicated process was drilled into soldiers as the “Load in Nine Times.” How soldiers achieved this in combat amid whizzing bullets beggars the imagination. The second problem was loading at the muzzle, which required moving between the two ends of a fairly long object. These two problems were answered with three interrelated inventions.

  • Enclosed metallic cartridges
  • Breech-loading mechanism
  • Magazine for multiple cartridges

Metallic Cartridges

Metallic cartridges developed over the remainder of the 19th century into the following form.

technology and firearm evidence presentation Rather than utilizing paper packets, ammunition was now enclosed in metal containers with the following components.

The operation is as follows. A firing pin, activated by the trigger mechanism, strikes a disk of shock-sensitive explosive known as the primer, which is embedded in the base of a brass cylinder called the case. The case also contains gunpowder, and its open end is sealed by a bullet, a conical mass of lead jacketed in copper, which is held in place by friction. The spark from the primer ignites the powder, causing an explosion. The resulting pressure releases the bullet from the case and sends it down the barrel. Cartridges are distinguished in power by their caliber, measured in terms of the width of the bullet at the widest point and the length of the case. The length of the case is correlated with its volume which, in turn, is related to how much gunpowder drives the bullet. English units refer only to the bullet width in inches. Metric units refer to both the bullet width and case length in millimeters. A common example is the rifle caliber .308. This number indicates a bullet diameter of .308 inches. Its metric designation is 7.62 x 51mm.

Locking Mechanisms and Magazines

With the cartridge contained in one unit, it was neither desirable nor possible to load it in the muzzle; it was necessary to load it in the breech. Opening the breech, however, posed grave danger. During the millisecond when a bullet travels down a barrel in modern rifles, the temperature reaches 5000 degrees F, the surface temperature of the sun. The ignition is very close to the shooter’s face. So, if one is going to open the breech with its layers of protective steel, one needs a means of reliably locking it up again. Two basic mechanisms emerged: a hand-operated lever and a rotating bolt of the kind commonly used in the stall doors of public bathrooms. The opening and closing of the bolt constituted a cycle that could be repeated. And the repetition, in turn, suggested the rapid, successive firing of cartridges. This development, in turn, led to the last of the three innovations, a magazine for holding multiple cartridges which could be rapidly loaded and fired. Magazines commonly took the form of a box in which cartridges are stacked in one or more columns and pushed upward into the rifle mechanism by a spring underneath them. Another common design was the drum in which cartridges are arranged in concentric layers, also powered by a spring which feeds them out of an exit port.

The Action of a Gun

A gun’s action is its central mechanism, and with the development of the metallic cartridges, locking mechanisms, and ammunition magazines, the modern action was essentially complete. Its heart is the receiver, a metal tube with cutouts or openings to accept the major components of a gun. (We will consider a rifle from which handgun mechanisms can be understood as a modification.) One end of the tube accepts the barrel for directing the bullet. Underneath the receiver is an opening to accept a magazine which feeds cartridges upwards. Directly behind the magazine is a trigger, which actuates the firing sequence. A lever can be attached behind the trigger, which can be moved forward and back to open and close the bolt. Or the bolt can be cycled by attaching a small handle at right angles to the bolt body that the shooter can rotate and push back and forth. The action is enclosed in a forestock to hold the weapon and a buttstock to brace it against the shoulder and align it for shooting. While complex in detail, the mechanism is very simple in principle. This was a design goal to make the weapon easier for soldiers to use under stress. Some have called it a distillation of industrialization wherein an individual takes input (cartridges), performs a simple repetitive motion (pulling the trigger and cycling the bolt), and produces output (the fired bullet). This correlation situates modern warfare as an outgrowth of industrialization.

Iconic Weapons

The developments above are demonstrated in famous historical weapons.

technology and firearm evidence presentation

The Model 1873 Winchester Rifle is widely recognized from John Wayne movies of the Old West and spaghetti Westerns. It is known as the “Gun That Won the West” although its status as a badge of individual heroism has been heavily revised in view of scholarship on the Western expansion. Appearing only 10 years after the Civil War, its operating lever, located behind the trigger, demonstrates one type of locking mechanism used for repeating weapons. Rather than being stacked in columns that protruded below the action, the cartridges were lined up nose-to-tail in a tube beneath the barrel, and a spring, located at the muzzle end, fed them into the action. Though designed as a rifle, the weapon utilized a pistol caliber cartridge allowing 10 cartridges to be loaded, about double the amount of contemporary handguns. The reasons for using a pistol caliber with a rifle were to allow the use of one caliber for both pistols and rifles while gaining extra velocity from the longer barrel of the rifle and increased ammunition capacity. Because of these design features and intermediate power, these and other lever actions have been described as the assault rifles of the 19th century. The Short Magazine Lee-Enfield (SMLE) was the service rifle of the British Empire from the late 19th century to the Korean War.

technology and firearm evidence presentation

Pictured is the SMLE No. 1 Mark III used in WWI. The bolt-action illustrates the other type of locking mechanism for repeating rifles. But the rifle was best known for its 10-round magazine placed just forward of the trigger; this was also the first detachable magazine. The culmination of bolt-action design was the Model 1898 Mauser invented in Germany by the brothers Peter and Paul Mauser.

technology and firearm evidence presentation

The rifle was the supreme achievement of everything that a bolt-action was supposed to be: efficient, strong, and safe. And it was manufactured to the highest standards at its factory at Oberndorf, Germany. As influential as the rifle design was the cartridge. German designers utilized the definition of kinetic energy, the energy of motion: Energy = (1/2)mv^2. This equation says that velocity makes a greater contribution to energy than mass, especially at higher values. The equation also says that reducing the amount of mass allows it to move at a greater velocity for a given amount of energy. Accordingly, designers reduced the size of bullets and gave them a pointed “spitzer” design for greater aerodynamic efficiency. The result was a cartridge with much greater accuracy and range. It was known as the .323 or 7.92 x 57mm, 8mm Mauser for short. This cartridge, mated with the Mauser design, showed immediate superiority over American forces in the Spanish-American War of 1898 and the British in the Boer War, and other countries eagerly adopted it. The American Springfield 1903 rifle was a virtual copy of the Mauser for which the United States paid a fee to Germany until America entered WWI in 1917. The Springfield’s cartridge, the 30.06 (.30 caliber developed in 1906) also closely copied the 8mm Mauser and remains the most popular hunting cartridge of all time. All modern bolt-action rifles that remain in use (for hunting and sniping) are based on the 1898 Mauser design.

Supreme Gun Designer

Despite the many people who have designed guns, one individual stands alone among them. John Moses Browning (1855-1926) was a Mormon from Utah and the son of a family of gun designers. He created his first original design at age 13 in his father’s workshop and spent his life at his craft. He died over his work desk in Belgium, over the design of one of his many classics known as the Browning Hi-Power, the precursor to the 9mm handguns that are the military and police standard today.

technology and firearm evidence presentation

Shown holding another of his famous creations, the Browning Auto 5 (A-5) semiautomatic shotgun, Browning was the Mozart of gun design. Not only was he at the summit of his craft, but he also demonstrated amazing versatility, designing the best-in-class guns of every type. His creation of semiautomatic and automatic mechanisms helped to shape the 20th century. And his designs and their derivatives provided virtually all the weapons for American soldiers in both World Wars.

The 20th Century and Automatic Weapons

Just as manually operated repeaters increased firepower over the muzzleloaders of the Civil War, designers looked for even greater increases in the rate of fire and lethality of rifles. The record for combat marksmanship was set by Sergeant Alfred Snoxall of the British Army before WWI, who hit a 12-inch diameter plate at a distance of 300 yards, 38 times in one minute with his SMLE. The British army as a whole was proficient in rapid rifle fire as demonstrated at the Battle of Mons (1914), where they overcame German soldiers armed with Mausers, and at the Battle of Gallipoli (1916), where they repulsed large numbers of attacking Turkish troops. Yet, such skill required extensive training. Machine guns, first appearing during the Civil War, addressed this problem by automating the shooting process with a hand crank and multiple, rotating barrels. However, the design could not be scaled down for personal weapons. While the next stage of development took place over a period of time and through several individuals, it can be understood through a single discovery by Browning who, characteristically, produced the best of the new weapons. Browning’s discovery demonstrates the observation of the Greek philosopher, Aristotle, that genius is the ability to use metaphor, that is, to see the relation between two unlike things.

technology and firearm evidence presentation

While just about everyone has seen grass blowing in the wind, few have made much of it.  Browning saw something different. He imagined the blowing wind as a gaseous medium and the bending grass as a rod, transferring energy from the gas. Why not, he reasoned, have the gases discharged to fire a cartridge directed to move a rod that could work the locking mechanism of a gun? That is, the gun’s own energy could operate itself, saving effort for the shooter and also dramatically speeding up the operation. This insight led to both semiautomatic and automatic weapons that remain as the current state of technology. Semiautomatic guns fire one shot with one pull of the trigger. Automatic guns continue to fire as long as the trigger remains depressed. Browning’s first invention was a gas-operated machine gun known as a “potato digger” for a reciprocating lever in front that suggested a digging motion. It was not particularly successful, but his gas operating principles remain the most successful technology for semiautomatic and automatic weapons today.

Browning’s Masterpiece

Curiously, with all of his rifles, machine guns and shotguns, Browning’s masterpiece is actually considered to be a handgun. Its genesis was the Spanish-American War (1898). Following the mysterious sinking of the battleship U.S.S. Maine in Havana Harbor, which has never been explained, American soldiers found themselves in the Philippines, fighting against indigenous people who were exchanging one colonizer (the Spanish) for another (Americans). Fighting in heavy jungle at close quarters, American soldiers found their bolt-action rifles to be ineffective and were forced to rely on sidearms.

technology and firearm evidence presentation

The American sidearm was a revolver chambered in the .38 Long Colt, and it proved inadequate. Highly motivated attackers would run down a stream of bullets to close with the shooter before expiring. The army turned to Browning for a solution. He decided to resurrect the heavier .45 Long Colt from frontier handguns and mate it with a semiautomatic handgun. His mechanism was called recoil-operation. Rather than utilizing the gases of discharge, the weapon used Newton’s Third Law of motion: For every action, there is an equal and opposite reaction. The process can be understood through the photo of his creation below.

technology and firearm evidence presentation

The handgun was designed so that part of it was fixed and part allowed to slide along a track.  The force of the discharged bullet forward exerts a force backwards on the gun. The lower part remains in place while the slide retracts. As it does so, a small hook (extractor) pulls on the rim of the empty case, dragging it backwards until it strikes a projection (ejector) that throws the case out at just the right speed and angle to exit the ejection port at the top of the slide.  Continuing to the rear, the slide cocks the hammer. In the meantime, with the breech clear, the next round is pushed upward from the magazine in the handgrip. The slide now returns forward under spring pressure, stripping off a new round and pushing it into the chamber where it is ready to be fired. Firing one round with each press of the trigger, the pistol’s seven-round magazine could be emptied in a little over one second. Browning’s redesigned cartridge, the .45 Automatic Colt Pistol (ACP), utilized a relatively heavy, slow-moving (speed of sound) bullet. Its impact could stop a running man in his tracks or flip a standing man backwards.  Combined with an extremely rapid operation, the pistol proved devastating.  However, it arrived too late for the Spanish-American war and entered service in 1911 which has led to its name, “1911”.  Apart from minor alterations, this handgun remained the official service pistol until 1985.  All modern semiautomatic pistols are based on Browning’s design.

The Devil’s Paintbrush

Machine guns were actually invented in 1885 by another influential inventor, Hiram Percy Maxim, an American. He used a somewhat different principle from Browning, recoil operation, similar to Browning’s 1911. Where Browning was an indifferent entrepreneur, who had disagreements with American companies like Winchester and ultimately left the United States to finish his career in Belgium, Maxim was a spectacular success in business. His entire career of firearms development was based on the advice of a friend who reportedly told him, “If you want to make money, find a way for the Europeans to cut each other’s throats faster.” Maxim proceeded to do precisely this, inventing a belt-fed, water-cooled, squad operated machine gun, which could reliably fire 500 rounds per minute.

technology and firearm evidence presentation

The suggestively named “Devil’s Paintbrush” produced a large flash at the muzzle, reminiscent of a paintbrush. And unlike rifles, which were designed for shooting point targets, the machine gun covered whole areas with destruction. Dean of gun historians, Ian Hogg, states that, “You could put an idiot behind the Devil’s Paintbrush, and still get your 500 rounds a minute.” The firepower of entire Civil War armies could now be wielded by a single soldier. Maxim’s machine gun was adopted by both sides in WWI and defined the trench warfare of that conflict. As a result, he achieved his dream, receiving honors from the European monarchs whose subjects he helped slaughter by the millions. But his work left him completely deaf by the end of his life.

WW1 Tactics and Weapons

Just as the rifled musket defined the battlefields of the Civil War, Maxim’s machine gun, combined with concentrated artillery fire, defined the battlefields of WWI (1914-1918). The outcome was largely the same. Faced with overwhelming fire, soldiers dug into the ground to protect themselves. The configuration of weapons elevated the defense over the offense, and the war settled into a stalemate for much of its four years. The trenches of the opposing side, separated by No-Man’s-Land, divided Europe from Belgium down to Italy. Each side mounted costly attacks that were repulsed with neither side gaining the upper hand. The futility of the war and its appalling cost were distilled into the fighting in Passchendaele, France. Not only were the soldiers forced to hide in the ground, but the ground itself, due to heavy rains and the relentless churning of bullets and shells, became a morass. One soldier reported to his commander that “it is not possible to consolidate porridge.”

technology and firearm evidence presentation

A British general, upon seeing the battlefield for the first time, broke down and exclaimed, “Good God! Did we send men to fight in that?” The fighting is also memorialized in Siegfried Sassoon’s poem “Memorial Tablet” in which the speaker says, “I died in hell/They called it Passchendaele.” Such was the impasse that it was only broken by geopolitical alliances and logistic changes resulting from the entry of the United States. Nevertheless, military minds were actively at work to solve the puzzle of the trenches. And while their inventions did not prove decisive in the war, they heavily influenced future conflicts. The basic problem of trench warfare was two-fold: How do you cross No-Man’s-Land, and how do you overcome the defenders of the trench on the opposite side? We will consider these problems in reverse. Soldiers, who reached the opposing trench, found themselves ill-equipped with their bolt-action rifles, which were unwieldy in close-quarters combat. They were difficult to operate and their capacity was small. In practice, the rifles amounted to little more than clubs. Soldiers resorted to 1911 pistols, which gained a reputation for effectiveness, but they were still sidearms. One solution was created by American general John M. Thompson.

technology and firearm evidence presentation His submachine gun was a carbine-length weapon that fired the .45 ACP cartridge on full automatic with a high rate of fire — about 800 rounds per minute. The drum, which holds 70 rounds, feeds the voracious appetite of this weapon, and the two pistol grips allow the shooter to retain control during the powerful recoil. The weapon was designed as a “trench broom” with which soldiers could sweep the trench clear of enemies and became the iconic “Tommy gun.” However, the weapon arrived too late to impact the war. With the cessation of hostilities, the army had no interest in the weapon, and Thompson cast about for ways to market it. Hardware stores offered it for sale at the (then expensive) price of $25, but failed to arouse the interest of the general public. But Prohibition gangsters found it highly desirable and used the submachine guns in large quantities. Their use in the Valentine’s Day Massacre (February 14, 1929) led directly to federal restrictions on machine guns as “unusual and dangerous weapons” in the National Firearms Act of 1934. The other problem of trench warfare was crossing No-Man’s-Land in the first place. A preparatory bombardment on the enemy trenches needed to be stopped well in advance to avoid killing their own side. During this lull, both sides raced into position, the attackers to cross to the other side, and the defenders to man their firing positions and set up their machine guns. Since the defenders had shorter to go, they invariably won. Some means was needed to suppress the fire of the defenders while the attackers were in transit. Bolt-action rifles were too  slow and difficult to operate on the run while submachine guns were too short-ranged and inaccurate. Once again the army turned to John Browning. He decided to modify a rifle to make it fully automatic. It was equipped with a box magazine which could be emptied with a pull of the trigger in two and a half seconds.

technology and firearm evidence presentation

The weapon, known as a Browning Automatic Rifle (BAR), was designed to be used in a technique known as “marching fire”. Holding the rifle at the hip, the soldier would fire a burst every third step or some regular interval, suppressing the enemy with the long range rifle cartridge as the attackers maintained their advance. Like the Tommy gun, the BAR arrived too late to have a significant impact on the war. However, it went on to a storied history afterwards as one of the first portable, medium machine guns. It was also the favored weapon of Clyde Barrow of the notorious criminal team of Bonnie and Clyde. Barrow obtained a BAR by raiding a National Guard Armory, and much of the team’s success was based on the fact that they were much more heavily armed than the police opposing them. Bonnie, herself, did not fire weapons, but she loaded Barrow’s magazines for him. The pair’s end came at the hands of police armed with the same weapons as them. Police ambushed the pair in a car that was slowed by a roadblock. First, the police emptied automatic rifles, then shotguns, and finally handguns into the car before it came to a stop. After the gangster era, the BAR served as a squad automatic weapon in American armies through the Korean War.


The Germans had their own version of technology and tactics to overcome trench warfare, and their efforts were so far-reaching as to have entered popular culture.

technology and firearm evidence presentation

The term “stormtroopers” conjures up the vaguely comical, armored soldiers of Star Wars, who get mowed down in large numbers by the heroic rebels. As it turns out, their appearance bears a distinct resemblance to their historical namesake from WWI.

technology and firearm evidence presentation

But here similarities come to an end, as the German stormtroopers were highly efficient soldiers who came very close to winning the war before American troops and weapons could arrive in force. The tactics of the stormtroopers can be inferred from their equipment. They were issued extra supplies of hand grenades as well as gas masks. They also carried their own brand of submachine guns as well as flamethrowers, a German invention. The stormtroopers’ tactics have become standard for modern armies and especially for Special Forces and relied on three principles: speed, surprise, and violent execution. These principles also persist in the slogan “Shock and Awe.”

The stormtroopers began their attack with poison gas. While the enemy was busy donning gas masks, the stormtroopers showered them with grenades and sprayed them with submachine guns. When the enemy broke, the stormtroopers did not turn sideways to consolidate a trench line but continued to the interior of the position where they would attack again. Considering an enemy position as an organism, the stormtroopers worked as a fast-moving virus, striking repeatedly and causing a systemic shock far out of proportion to their numbers. Their answer to trench warfare, not unlike the Americans, lay in the combination of mobility and firepower.

While their efforts ultimately failed, the stormtroopers went on to play an important role in the Nazi regime that followed. The shame and resentment felt by the defeated German population after the war was particularly acute for them as elite troops. Thus, they moved naturally into a new role as the brownshirt street thugs of the Sturmabteilung (SA) who helped propel Adolf Hitler to power. The name translates as “Storm Detachment” showing its antecedents in the stormtroopers. However, another irony lay in store for them. While Hitler appreciated the SA’s ability to disrupt the institutions of the Weimar Republic, he knew that ultimate power required the support of the professional German military which the SA hoped to replace. Thus as part of the “Night of the Long Knives” (June 30 to July 2, 1934) in which Hitler assassinated all of his political opponents, he eliminated the leadership of the SA, and the brownshirt rank and file melted back into the population.

But the stormtroopers’ legacy was not done. Hitler appreciated the idea of political soldiers devoted entirely to him, so he retained a cadre of personal bodyguards known as the Schutzstaffel (SS). These were then steadily extended into new organizations such as the secret police. With the outbreak of war, they were formed into combat units (Waffen SS),known for their fanaticism and atrocities, and ultimately became a parallel organization to the regular army.  The blitzkrieg method of warfare practiced by the German army also owed much to the stormtroopers. Even the U.S. Marines in the Pacific War made use of the stormtrooper doctrine in their island-hopping strategy, which hit key strongpoints, bypassing enemy units to be surrounded and overcome at leisure.

“The Greatest Battle Implement Ever Devised”

With WWII widely regarded as a continuation of the WWI, the interwar years were a period of preparation. During this time, the United States determined to develop a semiautomatic battle rifle to improve over bolt-action rifles by firing one round with each pull of the trigger. With automatic rifles like the BAR and semiautomatic pistols like the 1911, one might suppose that this would be a simple adaptation. However, in practice, it proved extraordinarily difficult. Solving this problem required the full attention of a mechanical genius for two decades. John Cantius Garand was a Canadian emigre who displayed signs of inventive brilliance from a young age.

technology and firearm evidence presentation

He was a crack shot who would astonish people at fairs by hitting every target at shooting galleries for hours. He also displayed eccentricities. Intrigued by ice skating, he maintained a rink in his living room for constant practice, which he only gave up on marrying in middle age. The Springfield Armory, the government arsenal for small arms, hired Garand and made the design of a semiautomatic rifle his only task. During exhaustive experimentation, Garand made a key breakthrough by adopting the long stroke piston of the BAR. This was a rod lying under the barrel which transmitted the gas of discharge backwards to operate the bolt.

As shown, Garand’s design bleeds off gas near the muzzle of the rifle and routes it to apply pressure on the operating rod. Browning’s original vision of grass blowing in the wind reached its full development here. The Rifle, Caliber .30, M1, as the army designated Garand’s creation, was completed in 1936, just in time for WWII. Mass-producing such a complicated and revolutionary design proved to be another challenge. Industrialists granted that the weapon was ingenious but claimed that it could not be produced on a large scale. Garand then showed that his ability was not limited to designing individual weapons but included entire production processes. He single-handedly invented new machinery that enabled production of the rifle for WWII. By the end of its manufacture in 1955, approximately five million of the rifles were made to the highest tolerances.

technology and firearm evidence presentation

The rifle proved to be not only accurate, powerful and fast, but extremely reliable despite the precision and exact timing required for semiauto operation. The mechanism worked flawlessly in tropical jungles, deserts, winter snows, and driving downpours, providing American soldiers a significant advantage over their Axis counterparts in every theater of operation. George S. Patton, the famously acerbic American general who commanded armored divisions, described the M1 rifle as “the greatest battle implement ever devised.” The success of the rifle led to a bill in Congress proposing to award Garand with special recognition and a sum of money for his contribution to the war effort. However, lawmakers decided that Garand’s salary at the Springfield Armory was sufficient and voted the bill down.

The Eastern Front: The Cradle of the Assault Rifle

In fact, the M1 Garand was not the most effective rifle of WWII, although because of its large numbers, it may have had the greatest impact on the war. To understand the most lethal rifle of the war, it is necessary to understand the environment and circumstances in which it was created. This environment was the Eastern Front where Germany and the Soviet Union fought each other. This front is obscure to the American historical sense because it was far removed, but it was also the center of gravity of WWII. While it is hard to discriminate among events of mass carnage — and while WWI, “The Great War,” had its uniquely horrifying aspects — there are concrete reasons why the Eastern Front of WWII may have been the greatest land conflict in history. It covered the most land area in thousands of miles of open steppe and forest. It involved the largest numbers of combatants. Nazi Germany lost five million dead against the 300,000 American casualties in all theaters of the war. Russian losses are unknown but have been estimated to be as high as 20 million soldiers and civilians. Both sides were filled with hatred that began as racial and ideological, but, after an exchange of atrocities, took on a life of its own. Typically neither side took prisoners, and desperate and fanatical fighting, such as that on the atolls of the Pacific enveloped an entire continent. Since the fighting was conducted as total warfare in Russian territory, their civilians also suffered terribly. Finally, the weather was abominable in all seasons with heat and dust in the summer and downpours and mud in the fall and spring. But worst was the winters where the temperatures routinely dropped to -40F. These brutal conditions worked to peel back the veneer of civilization even further.

technology and firearm evidence presentation

The circumstances of the Eastern Front have prevented widespread information about it. The Germans, on the losing side and with few survivors, were not disposed to write about their experience. Personal memoirs were not encouraged in the Soviet communist system. However, one memoir has emerged from the German side that many consider to be one of the foremost memoirs of this war, or any other. This memoir was written by Guy Sajer and entitled, The Forgotten Soldier . It chronicles the experience of a French teenager who volunteered for the Germany Army, the Wehrmacht, and fought through some of the worst combat on the Eastern Front. As a distillation of his experience, Sajer writes of his first contact with the battlefront. Having endured extreme hardship in winter as a supply soldier, including firsthand experience of death, he still perceived the front lines as something fundamentally different. “I remember seeing what looked like a disintegrating scarecrow flying through the rubble in a cone of flame, and falling in several pieces onto the edge of the trench, before rolling to the bottom…  I should perhaps end my account here, because my powers are inadequate for what I have to tell. Those who haven’t lived through the experience may sympathize as they read, the way one sympathizes with the hero of a novel or a play, but they certainly will never understand as one cannot understand the unexplainable. This stammering outpouring may be without interest to the sector of the world to which I now belong. However, I shall try to let my memory speak as clearly as possible… I shall try to reach and translate the deepest level of human aberration, which I never could have imagined, which I never would have thought possible, if I hadn’t known it firsthand.” (68-69) Such was the cauldron that produced the most lethal rifle of the war, the modern assault rifle. Yet, some antecedents of the assault rifle went all the way back to WWI. German military analysts found that the vast majority of fighting fell within a “combat radius” of 400 yards. Thus the materials that went into killing beyond that distance were largely wasted and demanded repurposing. Other factors were the weapons that the Germans faced on the Eastern Front. These included the Ppsh41, the Soviet tommy gun, and the 1891 Mosin-Nagant bolt-action rifle.

technology and firearm evidence presentation

technology and firearm evidence presentation

These were standard weapons of the time. However, the Soviets had many more of them with their enormous numerical superiority, and the Germans needed more than parity in response.

Sturmgewehr 44: The First Assault Rifle

In response to the demands of the battlefield, the Germans developed the Sturmgewehr (Stg) 44 whose name translates as “Assault Rifle.” Its model number is derived from the year of its issue, 1944.

technology and firearm evidence presentation

As can be seen, the Stg. 44 has several defining features. It was a carbine-length weapon which possesses a switch with three settings: safe (which renders the gun inoperable), semiautomatic, and automatic. The rifle has a large detachable magazine of 30 rounds to feed the automatic setting and a pistol grip, separate from the buttstock, to stabilize the weapon in rapid-fire. As innovative as anything else was the choice of caliber. Evidently, the rifle was a compromise between its antagonists, a submachine gun and a battle rifle, and this extended to the caliber. One would suppose that a middle choice of cartridge meant a middle choice of its two components, the case and bullet. However, the Germans took a different route, selecting the standard Mauser bullet with a shortened case for a new caliber, designated 7.92 X 33 Kurz. In part, the decision was determined by logistics. With its resources strained in the middle of a war, the Germans did not want to start production of a completely new round. But the caliber also neatly served their original design goal. With a shortened case, the new caliber subtracted the extra unnecessary energy of long-range rifle fire while maintaining the weight and striking power of a rifle round. And the smaller package allowed many more rounds to be carried than the standard rifle cartridges.

The new weapon proved extremely effective and by some accounts might have altered the course of the war had it been introduced in time and in sufficient numbers, just as the M1 Garand was supposed to have influenced the war in favor of the American army. For the reason for the weapon’s great success, one might look at its automatic capability, which had such a dramatic effect in the previous war. However, this is certainly not the case for a number of reasons. First, the Eastern Front was awash in automatic weapons of all sizes, shapes and calibers all the way up to automatic cannon, artillery that fired like machine guns. One more comparatively low-powered example would not have made much difference. Furthermore, there were severe limits on the use of the automatic setting. This mode would have consumed a soldier’s entire load of ammunition in a matter of seconds. We also know that the Stg. 44 was not designed to be a machine gun from its relatively slow rate of fire of about 450 rounds per minute. The automatic setting was designed to ensure hits with aimed fire rather than to work as an area suppression weapon. German doctrine called for the rifle to be used on its semiautomatic setting as much as possible.

The reasons for the rifle’s ascendancy can be traced to its interactions with its foes. With its different settings, the Stg. 44 had at least parity. On semiautomatic, it could trade shots with the Mosin-Nagant rifle; up close it could rival the volume of the Ppsh41. But with the flip of a switch, the Stg. 44 could gain an asymmetric advantage. Russian tommy gunners could be picked off before they could get in range, and soldiers charging with their bolt-action rifles could be outgunned by the automatic setting. By putting all these capabilities in a shortened weapon, the Germans gained mobility, which is another aspect of the term “assault.” One does not assault from a stationary position. Soldiers could charge forward less encumbered by the weapon. They could also retreat, either jumping into a truck, or fleeing on foot with less of a burden than a soldier with a full-size rifle. And mounted or on foot, the soldier was better able to conduct lateral maneuvers. It was thus a smart weapon which allowed soldiers to adapt to changing conditions with greatest efficiency, making each line soldier a general in his own right. The weapon also embodied the principles of mobility and firepower introduced so effectively by the stormtroopers of WWI. The assault rifle was a weaponized embodiment of their tactics.

The weapon’s success can be seen readily from subsequent history as virtually all subsequent service rifles are close copies of the design.

AK-47: The Ultimate Assault Rifle

While the Stg. 44 went out of production with the defeat of Nazi Germany, its legacy continued immediately with another weapon that remains in service and is still regarded as the supreme example of the type. The AK-47 (Automat Kalashnikov 1947) Assault Rifle was also born in the Eastern Front. It was designed by Mikhail Kalashnikov for whom it is named. A young tank officer recovering from wounds, he thought about a means to contribute to the struggle for his country and turned to his affinity for invention and design. His initial prototypes found favor with the Soviet military, and he was reassigned to develop them further. His rifle shows a clear indebtedness to the Stg. 44 in its general layout. Its caliber is also a direct copy combining a full-size rifle bullet with a shortened case. It is designated, 7.62X39mm.

technology and firearm evidence presentation

However, its interior and operating mechanism were significantly different. Much of it was derived from the M1 Garand that had proven so successful. By moving the Garand’s gas tube from under to over the barrel, one has the basic design of the AK-47. Thus, the weapon culminates the work of three titans of gun design: John Browning with his gas piston, John Garand with his semi-auto adaptation, and Mikhail Kalashnikov. One could hardly imagine a better pedigree for any weapon. But what was Kalashnikov’s contribution if he largely copied Garand’s design? It lay in a radical simplification. While Garand’s design was highly functional, it was extremely complex and required all the resources of American manufacturing at its height. Kalashnikov simplified the design so that it could be built cheaply in the workshops of the Third World and continue functioning in any conditions with a minimum of maintenance. This simplicity and robustness were key to its historical role.

While the AK-47 was never used in the defense of the Soviet Union for which it was designed, it played a crucial role in the Cold War struggle of ideologies. As part of the export of Communism, the AK-47 was sent in vast quantities to support Soviet satellites and to assist revolutions to bring more countries into their sphere. The AK-47 is the only rifle that appears on a national flag, that of Mozambique, in recognition of its role in establishing that country. Over 100 million copies of the weapon have been produced, far more than any other, to ensure its existence into the foreseeable future. Though not especially accurate, the AK-47 remains supreme at the design goals of the original assault rifle to produce acceptable accuracy out to 400 yards in high volume with unfailing reliability.

AR-15: “America’s Rifle”

With America’s success in WWII, it took longer to embrace a concept of the defeated foe. America’s version of the assault rifle did not appear until the beginning stages of the Vietnam War and took a somewhat different route. Rather than a close copy of the German design, the American weapon sought innovation. In many ways, it was a creature of its time, specifically, the Sputnik era when America was obsessed with technological improvement to surpass the Soviet Union. Rather than relying on established gun designers, the AR-15 was created by an aircraft engineer, Eugene Stoner, who sought to apply his expertise to guns. The designation “AR” means Armalite Rifle and refers to the Armalite aircraft corporation that was involved in its creation.

technology and firearm evidence presentation

Even decades later, the original design has the futuristic look of a space gun.

Stoner’s greatest innovation lay in the choice of caliber. In the quest for medium caliber ammunition, he reversed the decision of Russian and German designers. Rather than using a large bullet and a small case, Stoner opted for a large case and a small bullet. His caliber came to be called .223 or 5.56X45mm. The bullet diameter was comparable to a .22 rimfire, a recreational weapon for children, but Stoner harnessed it to the equation of Kinetic energy, E = (1/2)mv^2. A bullet of small mass enabled an increased velocity that was vastly enhanced with the extra powder of a larger case to achieve extreme levels. Essentially, he extended the logic of the Mauser brothers in using smaller, faster bullets. Where conventional rifle bullets travel at 2400 feet per second (fps) or about 2000 mph, the 5.56 bullets travel at over 3000 fps or about 3000 mph. While this resulted in somewhat improved accuracy with a flatter trajectory, the bullet design was largely motivated by more damaging wound ballistics as discussed in the next section.

Stoner’s other innovations were to extend the principles of the earlier assault rifles by using synthetic materials, especially plastic, to make it lighter and cheaper to build. He also removed Garand’s piston, choosing to let the discharge gases push directly against the bolt. This design feature known as Direct Gas Impingement (DGI) remains controversial and has not been reproduced in other designs.

The introduction of the AR-15, designated the M16A1, in the Vietnam War was not auspicious. The rifle rapidly acquired a reputation for jamming in the middle of combat with accounts of soldiers being found dead in the act of trying to disassemble and clean their rifles. For this reason and its plastic appearance, troops derided the rifle as the “Matty Mattel Toy.” It came off as distinctly inferior in encounters with the AK-47. The complaints finally triggered a Congressional investigation, which found that the army has substituted a different gun powder than the one specified to save money and had also erroneously instructed the soldiers that the rifle did not need cleaning. Corrections were made and the rifle has remained in service ever since although it continues to require close maintenance to keep functioning. Kalashnikov and Stoner met in person, and when asked his assessment of the AR-15, Kalashnikov stated the rifle was “pretty good” although it had gone through more versions “than the hair on my head.” He had a large head of bushy white hair at the time. The rifle remains in service with the United States military in approximately its sixth version with the designation M-4.

Wound Ballistics

Guns do their work through the bullet that strikes the target, so it is appropriate to examine their effects, especially on human targets that military weapons are designed for. During the retreat of the German Army in The Forgotten Soldier , Sajer describes an encounter between his unit and Russian villagers who are emboldened by the Germans’ imminent defeat. As the villagers begin shouting insults and hurling rocks at the heavily armed soldiers, Sajer watches as the hands of a comrade holding a machine gun begin shaking with anger and self-restraint. The soldier calls out, “Watch it, you pigs, or we’ll drill you full of holes.” This is an accurate description of the effect of a bullet.

technology and firearm evidence presentation

Upon striking a human body, a bullet disintegrates everything in its path, leaving a tunnel behind it. Where the bullet destroys vital systems, such as organs, arteries, and major veins, death is instantaneous. The wound channel also allows for extravasation, the loss of blood from the body, that can lead to death as well. But the bullet does even more.

There is too much kinetic energy contained in a bullet for it to be released only forward, and it also exits sideways. The destruction caused here reveals that the bullet itself is not the only or even primary agent of destruction in a gunshot. It is more of a trigger that initiates another physical process to cause damage. This other physical process is based on the fact that the vast majority of the human body, other than a few pounds of chemicals, consists of water, and it is this seemingly-innocuous and universal substance that is the agent of damage. The relevant feature of water is that it is incompressible. This seems unintuitive with our daily experience of water flowing over and around us. Yet it can be seen in the everyday act of holding water cupped in both hands, and then squeezing your hands together to make the water squirt out. The supersoaker water gun operates by the same principle. Water does not absorb pressure but moves in response. When enclosed in a container, water transmits pressure instantaneously to all parts of the container.

The human body can be modeled as a series of enclosed containers of water down to the microscopic level of the cell, the subunit of the body, which is essentially a small bag of water. Once the pressure exceeds a certain limit, the container ruptures like a water balloon. This is  the effect of energy released laterally from a bullet traveling through the body. Like a balloon, containers of water in the human body expand in a process of cavitation which is subdivided into two types:  permanent and temporary cavitation. When the elastic limit of the membrane is exceeded, it ruptures in permanent cavitation; just like a rubber band that has been snapped, the membrane cannot reform. Minus the energy required to do this, the energy wave continues onward. After a point, the energy drops below the elastic limit, and the tissue structures can rebound like a rubber band in temporary cavitation. But even here, there are gradations. Just as a rubber band, after repeated stretching, loses elasticity, so do tissues that have been stretched up to a certain point. The wave of hydrostatic pressure, moving radially outward from the bullet’s path, is responsible for much of the damage of gunshots to human bodies.

The caliber innovation of the AR-15 rifle introduced a variation on this process. Stoner’s main reason for increasing the bullet velocity in the 5.56X45mm caliber was to cause additional damage. The stability of rifle bullets, which permitted long-range accuracy during the Civil War, depends on a close relationship between bullet weight, velocity, and rotation (induced by rifling). Disturb any factor, and the bullet becomes unstable. Stoner changed all these variables by reducing the bullet weight, increasing velocity, and reducing the rotation rate. When these bullets struck a body, they behaved erratically. This began with a tumbling effect wherein the bullet began cartwheeling through tissue, creating a much wider and more ragged channel with its long axis, rather than its diameter. In addition to instability in orientation, the 5.56mm bullets were also unstable in direction. When encountering bone or different tissue density, the bullets would carom off, making a new path of destruction. Rather than a straight tunnel, the 5.56mm bullets would tear a zigzag channel with more lateral cavitation than other calibers. This explains the comments of some doctors that wounds from these rounds “look like a bomb had gone off in there.” And they also explain how even when wounds are sewn up, they sometimes collapse. This indicates semi-permanent cavitation where, even though a structure has survived, it has suffered such deep fibrous tearing that it can no longer support itself. There is a general medical opinion that wounds to the thorax with this caliber are typically fatal.

Does this mean that the 5.56X45mm caliber is more lethal than the 7.62X39mm caliber of the AK-47? Not necessarily. As with other of Stoner’s innovations, his choice of caliber had unforeseen drawbacks. While bullet instability could produce larger wounds, it would not always. Sometimes, the bullet would deflect out of the body in a harmless direction. It is also easily deflected by obstacles such as panes of glass or tree leaves, or simply stopped by barriers that would not deter heavier calibers. Other times, the bullet’s energy would be used up in a meandering pathway and remain in the body without causing the deadly extravasation. The slow bullet rotation of the original caliber also degraded accuracy, making it harder to hit the target. However, increasing the rotation decreased the bullet’s destructiveness, and the small bullets would sometimes punch straight through a body without causing serious damage. Finally, where the small bullets take advantage of kinetic energy by tearing body structures, they are disadvantaged by the properties of momentum. Momentum defined as (mass X velocity), requires sufficient mass to knock down a target, just as a billiard ball requires a sufficient mass to move another billiard ball. Unlike John Browning’s heavy .45 ACP bullets, the 5.56mm bullets do not knock down targets, which has a special value in a combat environment. The injured target must then coordinate its limbs while in shock and work against gravity to stand up, making the soldier less of a threat.

In contrast, the heavier .30 caliber bullets of the AK-47 can knock the assailant down, and the gun platform can deliver these bullets much faster than a full-power rifle. Thus, there are two kinds of “assault rifle ammunition” with different effects. While the smaller 5.56X45mm ammunition has more of a mutilating, shredding effect than the 7.62X39mm, neither is ultimately more dangerous than the other.

What is an assault rifle?

The history of firearms can shed light on one of the foremost issues of gun violence. This discussion is driven by the unprecedented number of mass shootings which are often carried out with a version of the AR-15 rifle. As a way to eliminate this crime, it has been proposed to ban Ar-15s as part of the category of assault rifles, similar to the way that machine guns were regulated after the gangster-era as “unusual and dangerous weapons.” However, the proposed regulation begs the question of what exactly is an assault rifle. The weapons used in the shootings are civilian versions of the M-16 series of rifle, virtually identical except for the selector switch for fully automatic fire.

technology and firearm evidence presentation The two sides of gun control and gun rights have a deep interest in this definition. Defining AR-15 rifles as assault weapons is a prerequisite towards regulating them as desired by the gun control faction and resisted by the gun rights movement. As found with other topics of cultural discourse, everything hinges on the definition used, and each side has found a definition to suit its purpose. We will briefly review the two sides and the arguments for and against found in the popular conversation. Supporters of gun rights cite the U.S. Army for a definition that an assault rifle has a selective fire capability, including a setting for fully automatic fire. Since civilian AR-15 do not have this capability, they do not meet the definition and should not be regulated. However, neither the National Rifle Association (NRA) or anyone else has referenced a specific document published by the U.S. Army with this definition. On the other hand, proponents of gun control define an assault rifle with the definition used by the Assault Weapons Ban (AWB). This definition was based on six “evil features” (a gun rights term).

  • Flash hider
  • Attachment point for a bayonet
  • Rails for a grenade launcher
  • Large, detachable magazine
  • Pistol grip
  • Folding stock

An assault rifle is defined as any rifle having a large, detachable magazine (item 4) and any other two on the list; this would include civilian AR-15 rifles. Gun rights supporters argue that this definition is flawed in only considering the outward, “cosmetic” appearance of the weapon and not the action that is more essential. Since the semiautomatic action of the civilian AR-15s is identical to many other weapons not considered for banning (such as the M1 Garand), the definition is considered misguided and unfair to owners of these weapons. These are the major points of debate on banning assault rifles, which is currently deadlocked. Both definitions can be understood as theories or abstractions about their subject, so a possible new line of inquiry could consider the counterpart of theory: reality or history. Doing so can make two contributions to the discussion. The first is in response to another point advanced by gun rights supporters that the term “assault rifle” is not even a specialized military term but a completely arbitrary designation. Any gun, weapon, or even implement, such as an automobile, used for violence, can be labeled an “assault weapon” according to this argument. However, history shows that the term “assault rifle” is not arbitrary at all. It was a historical term, referring to a distinctive type of weapon which had an important, measurable impact on history and on the subsequent design of weapons. To deny the existence of such a weapon flies in the face of facts and makes history less, rather than more, comprehensible. The historical record suggests that there is value in recognizing a type of weapon called an “assault rifle” based on the features of the original weapon of that name, the Stg. 44. Secondly, history makes clear that the assault rifle was not an entirely original creation such as Browning’s gas design, inspired by grass in the wind. Rather, the assault rifle combines technologies developed over a long period of time including carbines (shortened rifles), detachable magazines, gas-operated semi-automatic weapons, machine guns, and pistol grips. This composite history suggests that there is no exact line distinguishing an assault rifle from other guns but rather a series of degrees. In determining the degree of difference, one would focus, naturally, on the automatic feature which is the only one separating the civilian AR-15 rifle from the military version.  One can do this by examining the automatic feature in the doctrine of the Stg. 44 and the U.S. Army today, but an exact determination here as well as the legal implications remain to be discussed.


Constitutional History

  • Cottrol, R. J. (1994). Gun Control and the Constitution: Sources and Explorations on the Second Amendment . New York: Garland Publishers.  Shields Library   General Collection   A7 G86 1994
  • Cramer, C. E. (1999). Concealed Weapon Laws of the Early Republic: Duelling, Southern Violence, Moral Reform . Westport: Praeger.  Shields Library   General Collection   KF3941 .C729 1999
  • Cornell, S. (2006). A Well-Regulated Militia: The Founding Fathers and the Origins of Gun Control in America . New York: Oxford University Press.  Shields Library   General Collection   KF4558 2nd .C67 2006
  • Cornell, S., & Shallhope, R. E. (2000). Whose Right to Bear Arms Did the Second Amendment Protect? Boston: Bedford/St. Martin’s. Shields Library   General Collection   KF4558 2nd .W567 2000
  • Defensor, C. (1970). Gun Registration Now–Confiscation Later? New York: Vantage Press. Shields Library   General Collection   HV8059 .D44
  • Freedman, W. (1989). The Privilege to Keep and Bear Arms: The Second Amendment and Its Interpretation . New York: Quorum Books.  Shields Library   General Collection   KF3941 .F74 1989
  • Gottlieb, A. M. (1981). The Rights of Gun Owners . Aurora: Caroline House Publishers. Shields Library   General Collection   KF3941 .G674
  • Kates, D. B. (1979). Restricting Handguns: The Liberal Skeptics Speak Out . Croton-on-Hudson: North River Press.  Shields Library   General Collection   A75 R47
  • Winkler, A. (2011). Gunfight: The Battle Over the Right to Bear Arms in America . New York: W.W. Norton & Company.  Shields Library   General Collection   KF3941 .W56 2011
  • Uviller, H. R., & Merkel, W. G. (2002). The Militia and the Right to Arms, or, How the Second Amendment Fell Silent . Durham, NC: Duke University Press. Shields Library   General Collection   UA42 .U95 2002

  Military History

  • Bull, S., & Rottman, G. (2008). Infantry Tactics of the Second World War . New York: Oxford. Shields Library   General Collection   UD157 .B85 2008
  • Bull, S. (2010). Trench: A History of Warfare on the Western Front . Oxford: Osprey Publications.  Shields Library   General Collection   D530 .B848 2010
  • Carman, W. Y. (1955). A History of Firearms From Earliest Times to 1914 . New York: St. Martin’s Press.
  • Chickering, R., & Forster, S. (2000). Great War, Total War: Combat and Mobilization on the Western Front, 1914-1918 . Cambridge: Cambridge University Press.  Shields Library   General Collection   D530 .G68 2000
  • Coates, E. J., & Dean, T. S. (1990). An Introduction to Civil War Small Arms . Gettysburg, PA: Thomas Publications.
  • Cramer, C. E. (2006). Armed America: The Remarkable Story of How and Why Guns Became as American as Apple Pie . Nashville, TN: Nelson Current.  Shields Library   General Collection   HV8059 .C73 2006
  • Hogg, I. V., & Weeks, J. S. (1985). Military Small Arms of the 20th Century: A Comprehensive Illustrated Encyclopedia of the World’s Small-Calibre Firearms . London: Arms & Armour Press.  Shields Library   General Collection   UD380 .H58 1985b
  • Horwitz, J., & Anderson, C. (2009). Guns, Democracy, and the Insurrectionist Idea . Ann Arbor, MI: University of Michigan Press. Shields Library   General Collection   U5 H626 2009
  • Jones, K. R., Macolo, G., & Welch, D. (2013). A Cultural History of Firearms in the Age of Empire . Burlington: Ashgate. Shields Library   General Collection   G7 C85 2013
  • King, A. (2013). The Combat Soldier: Infantry Tactics and Cohesion in the 20th and 21st Centuries . Oxford: Oxford University Press.  Shields Library   General Collection   UD157 .K56 2013       
  • Sajer, G. (1971). The Forgotten Soldier . New York: Harper & Row. Shields Library   General Collection   D764 .S234513
  • Samuels, M. (1992). Doctrine and Dogma: German and British Infantry Tactics in the First World War . New York: Greenwood Press.  Shields Library   General Collection   3 .S26 1992     
  • Senich, P. R. (1987). The German Assault Rifle: 1935-1945 . Boulder: Paladin Press.  Shields Library   General Collection   G4 S46 1987
  • Silverman, D. (2016). Thundersticks: Firearms and the Violent Transformation of Native America . Cambridge: Belknap Press.  Shields Library   General Collection   W2 S55 2016

Gun Violence/Crime

  • DeConde, A. (2001). Gun Violence in America: The Struggle for Control . Boston: Northeastern University Press.  Shields Library   General Collection   HV7436 .D43 2001
  • Giffords, G. D., & Kelly, M. E. (2014). Enough: Our Fight to Keep America Safe From Gun Violence . New York: Scribner.  Shields Library   General Collection   HV7436 .G54 2014
  • Kellner, D. (2008). Guys and Guns Amok: Domestic Terrorism and School Shootings from the Oklahoma City Bombings to the Virginia Tech Massacre . Boulder, CO: Paradigm Publishers.  Shields Library   General Collection   U6 K45 2008
  • National Research Council (U.S.) Committee to Improve Research Information and Data on Firearms, Wellford, C. F., Pepper, J., Petrie, C., & National Research Council (U.S.). Committee on Law and Justice. (2004). Firearms and Violence:  A Critical Review . Washington, D.C.: National Academies Press.  Shields Library   General Collection   HV6789 .N37 2004
  • Schorr, K. (2017). Shot: 101 Survivors of Gun Violence in America . Brooklyn, NY: PowerHouse Books.  Shields Library   General Collection   3.U5 S56 2017
  • Younge, G. (2016). Another Day in the Death of America:  A Chronicle of Ten Short Lives.  New York:  Nation Books.  Shields Library General Collection HN90.V5Y675 2016


  • American Rifleman Magazine. National Rifle Association. (1923). American Rifleman . Washington: National Rifle Association.
  • Dray, P. (2018). The Fair Chase: The Epic Story of Hunting in America . New York: Basic Books.  Shields Library   General Collection   SK41 .D73 2018
  • Duda, M. D., Jones, M. F., & Criscione, A. (2010). Sportsman’s Voice:  Hunting and Fishing in America . State College, PA: Venture Pub.  Shields Library   General Collection   SK41 .D83 2010
  • Grey, H., & McCluskey, R. (1955). Field & Stream Treasury: A Selection of Memorable Articles From America’s Number One Sportsman’s Magazine . New York: Holt.  Shields Library   General Collection   SK33 .F45
  • Herman, D. J. (2001). Hunting and the American Imagination Washington D.C.: Smithsonian Institute Press. Shields Library   General Collection   SK40 .H47 2001
  • Roosevelt, T. (1893). The Wilderness Hunter: An Account of the Big Game of the United States and Its Chase with Horse, Hound, and Rifle . New York: G.P. Putnam & Sons.  Shields Library   General Collection   SK45 .R6
  • United States Department of the Interior. (1991). Enjoy Outdoors America: Hunting . (Shields Library   Gov Info & Maps   DOC I 1.2:H 92   ). Washington, D.C.: U.S. Department of the Interior.  Shields Library   Gov Info & Maps   DOC I 1.2:H 92
  • Identifying Armed Respondents to Domestic Violence Restraining Orders and Recovering Their Firearms: Process Evaluation of an Initiative in California .  Garen J. Wintemute, MD, MPH, Shannon Frattaroli, PhD, MPH, Barbara E. Claire, Katherine A. Vittes, PhD, MPH and Daniel W. Webster, ScD, MPH.  American Journal of Public Health , published online ahead of print December 12, 2013;e1-e6. doi:10.2105/AJPH.2013.301484.
  • Support for a Comprehensive Background Check Requirement and Expanded Denial Criteria for Firearm Transfers: Findings from the Firearms Licensee Survey . Garen J Wintemute.  Journal of Urban Health:  Bulletin of the New York Academy of Medicine . Published online 08 November 2013. DOI:10.1007/s11524-013-9842-7.
  • Comprehensive Background Checks for Firearm Sales . Garen J Wintemute.  In: Webster W, Vernick J (eds).  Reducing Gun Violence in America. The Johns Hopkins University Press; 2013.  pp 95-107.
  • Karlson, T. A., & Hargarten, S. W. (1997). Reducing Firearm Injury and Death: A Public Health Sourcebook on Guns . New Brunswick: Rutgers University Press.  Carlson Health Sci Library   General Collection   WO807 K18r 1997
  • Ladenheim, J. C., & Ladenheim, E. D. (1996). Firearms and Ballistics for Physician and Attorney . Chapel Hill, N.C.: Professional Press. Carlson Health Sci Library   General Collection   WO807 L34 1996
  • Owen-Smith, M. S. (1981). High Velocity Missile Wounds . London: E. Arnold. Carlson Health Sci Library   General Collection   WO807 O94 1981
  • Removing Guns from Batterers: Findings from a Pilot Survey of Domestic Violence Restraining Order Recipients in California . Katherine A Vittes, Daniel W Webster, Shannon Frattaroli, Barbara E Claire, Garen J Wintemute.  Violence Against Women ; 2013 19(5):602-616.
  • Swan, K. G., & Swan, R. C. (1989). Gunshot Wounds: Pathophysiology and Management . Chicago: Yearbook Medical Publishers.  Carlson Health Sci Library   General Collection   WO807 S93 1989
  • Hemenway, D. (2004). Private Guns, Public Health . Ann Arbor, MI: University of Michigan Press. Carlson Health Sci Library   General Collection   WO 807 H498p 2004
  • Tsokos, G. C., & Atkins, J. L. (2003). Combat Medicine: Basic and Clinical Research in Military, Trauma, and Emergency Medicine . Totowa, NJ: Humana Press.  Carlson Health Sci Library   General Collection   WO 800 C7294 2003
  • Warlow, T. A. (2005). Firearms, The Law, and Forensic Ballistics . Boca Raton, FL: CRC Press.  Carlson Health Sci Library   General Collection   W 700 W27 2005  
  • Zwerling, C., & McMillan, D. (1993). Firearms Injuries: A Public Health Approach . New York: Oxford University Press.  Carlson Health Sci Library   General Collection   W1 AM592 v.9 no.3 suppl.
  • Alexander, M. (2012). The New Jim Crow: Mass Incarceration in the Age of Color-blindness . New York: The New Press.  Shields Library   General Collection   HV9950 .A437 2010
  • Bakal, C. (1966). The Right to Bear Arms . New York: McGraw-Hill. Shields Library   General Collection   HV8059 .B3
  • Barlow, H. D. (2000). Criminal Justice in America . Upper Saddle River, NJ: Prentice Hall. Shields Library   General Collection   HV9950 .B36 2000
  • Braman, D. (2007). Doing Time on the Outside: Incarceration and Family Life in Urban America . Ann Arbor: University of Michigan Press.    Shields Library   General Collection   HV9950 .B7 2004  
  • Baum, D. (2013). Gun Guys: A Road Trip . New York: Knopf.  Shields Library   General Collection   HV8059 .B38 2013
  • Canada, G. (1995). Fist, Stick, Knife, Gun: A Personal History of Violence in America . Boston: Beacon Press.  Shields Library   General Collection   V55 C36 1995
  • Carlson, J. (2015). Citizen-Protectors: The Everyday Politics of Guns in an Age of Decline . Oxford: Oxford University Press.  Shields Library   General Collection   HV8059 .C37 2015
  • Farr, V., Myrttinen, H., & Schnabel, A. (2009). Sexed Pistols: The Gendered Impact of Small Arms and Light Weapons . Tokyo: United Nations University Press.  Shields Library   General Collection   HV7435 .S49 2009
  • Harrington, M. (2012). The Other America: Poverty in the United States . New York: Scribner.    Shields Library   General Collection   HV91 .H3
  • Kukla, R. J. (1973). Gun Control . Harrisburg, PA: Stackpole Books. Shields Library   General Collection   HV8059 .K79
  • Kohn, A. A. (2004). Shooters: Myths and Realities of America’s Gun Culture . Oxford: Oxford University Press.  Shields Library   General Collection   HV8059 .K65 2004
  • Lepore, J. (2010). The Whites of Their Eyes: The Tea Party’s Revolution and the Battle over American History . Princeton, NJ: Princeton University Press.  Shields Library   General Collection   9 .L46 2010
  • Prothrow-Stith, D., & Weissman, M. (1993). Deadly Consequences: How Violence Is Destroying Our Teenage Population and a Plan to Begin Solving the Problem. New York: HarperPerennial.  Shields Library   General Collection   4.Y68 P76 1991

Doha Declaration

Education for justice.

  • Agenda Day 1
  • Agenda Day 2
  • Agenda Day 3
  • Agenda Day 4
  • Registration
  • Breakout Sessions for Primary and Secondary Level
  • Breakout Sessions for Tertiary Level
  • E4J Youth Competition
  • India - Lockdown Learners
  • Chuka, Break the Silence
  • The Online Zoo
  • I would like a community where ...
  • Staying safe online
  • Let's be respectful online
  • We can all be heroes
  • Respect for all
  • We all have rights
  • A mosaic of differences
  • The right thing to do
  • Solving ethical dilemmas
  • UNODC-UNESCO Guide for Policymakers
  • UNODC-UNESCO Handbooks for Teachers
  • Justice Accelerators
  • Introduction
  • Organized Crime
  • Trafficking in Persons & Smuggling of Migrants
  • Crime Prevention & Criminal Justice Reform
  • Crime Prevention, Criminal Justice & SDGs
  • UN Congress on Crime Prevention & Criminal Justice
  • Commission on Crime Prevention & Criminal Justice
  • Conference of the Parties to UNTOC
  • Conference of the States Parties to UNCAC
  • Rules for Simulating Crime Prevention & Criminal Justice Bodies
  • Crime Prevention & Criminal Justice
  • Engage with Us
  • Contact Us about MUN
  • Conferences Supporting E4J
  • Cyberstrike
  • Play for Integrity
  • Running out of Time
  • Zorbs Reloaded
  • Developing a Rationale for Using the Video
  • Previewing the Anti-Corruption Video
  • Viewing the Video with a Purpose
  • Post-viewing Activities
  • Previewing the Firearms Video
  • Rationale for Using the Video
  • Previewing the Human Trafficking Video
  • Previewing the Organized Crime Video
  • Previewing the Video
  • Criminal Justice & Crime Prevention
  • Corruption & Integrity
  • Human Trafficking & Migrant Smuggling
  • Firearms Trafficking
  • Terrorism & Violent Extremism
  • Introduction & Learning Outcomes
  • Corruption - Baseline Definition
  • Effects of Corruption
  • Deeper Meanings of Corruption
  • Measuring Corruption
  • Possible Class Structure
  • Core Reading
  • Advanced Reading
  • Student Assessment
  • Additional Teaching Tools
  • Guidelines for Stand-Alone Course
  • Appendix: How Corruption Affects the SDGs
  • What is Governance?
  • What is Good Governance?
  • Corruption and Bad Governance
  • Governance Reforms and Anti-Corruption
  • Guidelines for Stand-alone Course
  • Corruption and Democracy
  • Corruption and Authoritarian Systems
  • Hybrid Systems and Syndromes of Corruption
  • The Deep Democratization Approach
  • Political Parties and Political Finance
  • Political Institution-building as a Means to Counter Corruption
  • Manifestations and Consequences of Public Sector Corruption
  • Causes of Public Sector Corruption
  • Theories that Explain Corruption
  • Corruption in Public Procurement
  • Corruption in State-Owned Enterprises
  • Responses to Public Sector Corruption
  • Preventing Public Sector Corruption
  • Forms & Manifestations of Private Sector Corruption
  • Consequences of Private Sector Corruption
  • Causes of Private Sector Corruption
  • Responses to Private Sector Corruption
  • Preventing Private Sector Corruption
  • Collective Action & Public-Private Partnerships against Corruption
  • Transparency as a Precondition
  • Detection Mechanisms - Auditing and Reporting
  • Whistle-blowing Systems and Protections
  • Investigation of Corruption
  • Introduction and Learning Outcomes
  • Brief background on the human rights system
  • Overview of the corruption-human rights nexus
  • Impact of corruption on specific human rights
  • Approaches to assessing the corruption-human rights nexus
  • Human-rights based approach
  • Defining sex, gender and gender mainstreaming
  • Gender differences in corruption
  • Theories explaining the gender–corruption nexus
  • Gendered impacts of corruption
  • Anti-corruption and gender mainstreaming
  • Manifestations of corruption in education
  • Costs of corruption in education
  • Causes of corruption in education
  • Fighting corruption in education
  • Core terms and concepts
  • The role of citizens in fighting corruption
  • The role, risks and challenges of CSOs fighting corruption
  • The role of the media in fighting corruption
  • Access to information: a condition for citizen participation
  • ICT as a tool for citizen participation in anti-corruption efforts
  • Government obligations to ensure citizen participation in anti-corruption efforts
  • Teaching Guide
  • Brief History of Terrorism
  • 19th Century Terrorism
  • League of Nations & Terrorism
  • United Nations & Terrorism
  • Terrorist Victimization
  • Exercises & Case Studies
  • Radicalization & Violent Extremism
  • Preventing & Countering Violent Extremism
  • Drivers of Violent Extremism
  • International Approaches to PVE &CVE
  • Regional & Multilateral Approaches
  • Defining Rule of Law
  • UN Global Counter-Terrorism Strategy
  • International Cooperation & UN CT Strategy
  • Legal Sources & UN CT Strategy
  • Regional & National Approaches
  • International Legal Frameworks
  • International Human Rights Law
  • International Humanitarian Law
  • International Refugee Law
  • Current Challenges to International Legal Framework
  • Defining Terrorism
  • Criminal Justice Responses
  • Treaty-based Crimes of Terrorism
  • Core International Crimes
  • International Courts and Tribunals
  • African Region
  • Inter-American Region
  • Asian Region
  • European Region
  • Middle East & Gulf Regions
  • Core Principles of IHL
  • Categorization of Armed Conflict
  • Classification of Persons
  • IHL, Terrorism & Counter-Terrorism
  • Relationship between IHL & intern. human rights law
  • Limitations Permitted by Human Rights Law
  • Derogation during Public Emergency
  • Examples of States of Emergency & Derogations
  • International Human Rights Instruments
  • Regional Human Rights Instruments
  • Extra-territorial Application of Right to Life
  • Arbitrary Deprivation of Life
  • Death Penalty
  • Enforced Disappearances
  • Armed Conflict Context
  • International Covenant on Civil and Political Rights
  • Convention against Torture et al.
  • International Legal Framework
  • Key Contemporary Issues
  • Investigative Phase
  • Trial & Sentencing Phase
  • Armed Conflict
  • Case Studies
  • Special Investigative Techniques
  • Surveillance & Interception of Communications
  • Privacy & Intelligence Gathering in Armed Conflict
  • Accountability & Oversight of Intelligence Gathering
  • Principle of Non-Discrimination
  • Freedom of Religion
  • Freedom of Expression
  • Freedom of Assembly
  • Freedom of Association
  • Fundamental Freedoms
  • Definition of 'Victim'
  • Effects of Terrorism
  • Access to Justice
  • Recognition of the Victim
  • Human Rights Instruments
  • Criminal Justice Mechanisms
  • Instruments for Victims of Terrorism
  • National Approaches
  • Key Challenges in Securing Reparation
  • Topic 1. Contemporary issues relating to conditions conducive both to the spread of terrorism and the rule of law
  • Topic 2. Contemporary issues relating to the right to life
  • Topic 3. Contemporary issues relating to foreign terrorist fighters
  • Topic 4. Contemporary issues relating to non-discrimination and fundamental freedoms
  • Module 16: Linkages between Organized Crime and Terrorism
  • Thematic Areas
  • Content Breakdown
  • Module Adaptation & Design Guidelines
  • Teaching Methods
  • Acknowledgements
  • 1. Introducing United Nations Standards & Norms on CPCJ vis-à-vis International Law
  • 2. Scope of United Nations Standards & Norms on CPCJ
  • 3. United Nations Standards & Norms on CPCJ in Operation
  • 1. Definition of Crime Prevention
  • 2. Key Crime Prevention Typologies
  • 2. (cont.) Tonry & Farrington’s Typology
  • 3. Crime Problem-Solving Approaches
  • 4. What Works
  • United Nations Entities
  • Regional Crime Prevention Councils/Institutions
  • Key Clearinghouses
  • Systematic Reviews
  • 1. Introduction to International Standards & Norms
  • 2. Identifying the Need for Legal Aid
  • 3. Key Components of the Right of Access to Legal Aid
  • 4. Access to Legal Aid for Those with Specific Needs
  • 5. Models for Governing, Administering and Funding Legal Aid
  • 6. Models for Delivering Legal Aid Services
  • 7. Roles and Responsibilities of Legal Aid Providers
  • 8. Quality Assurance and Legal Aid Services
  • 1. Context for Use of Force by Law Enforcement Officials
  • 2. Legal Framework
  • 3. General Principles of Use of Force in Law Enforcement
  • 4. Use of Firearms
  • 5. Use of “Less-Lethal” Weapons
  • 6. Protection of Especially Vulnerable Groups
  • 7. Use of Force during Assemblies
  • 1. Policing in democracies & need for accountability, integrity, oversight
  • 2. Key mechanisms & actors in police accountability, oversight
  • 3. Crosscutting & contemporary issues in police accountability
  • 1. Introducing Aims of Punishment, Imprisonment & Prison Reform
  • 2. Current Trends, Challenges & Human Rights
  • 3. Towards Humane Prisons & Alternative Sanctions
  • 1. Aims and Significance of Alternatives to Imprisonment
  • 2. Justifying Punishment in the Community
  • 3. Pretrial Alternatives
  • 4. Post Trial Alternatives
  • 5. Evaluating Alternatives
  • 1. Concept, Values and Origin of Restorative Justice
  • 2. Overview of Restorative Justice Processes
  • 3. How Cost Effective is Restorative Justice?
  • 4. Issues in Implementing Restorative Justice
  • 1. Gender-Based Discrimination & Women in Conflict with the Law
  • 2. Vulnerabilities of Girls in Conflict with the Law
  • 3. Discrimination and Violence against LGBTI Individuals
  • 4. Gender Diversity in Criminal Justice Workforce
  • 1. Ending Violence against Women
  • 2. Human Rights Approaches to Violence against Women
  • 3. Who Has Rights in this Situation?
  • 4. What about the Men?
  • 5. Local, Regional & Global Solutions to Violence against Women & Girls
  • 1. Understanding the Concept of Victims of Crime
  • 2. Impact of Crime, including Trauma
  • 3. Right of Victims to Adequate Response to their Needs
  • 4. Collecting Victim Data
  • 5. Victims and their Participation in Criminal Justice Process
  • 6. Victim Services: Institutional and Non-Governmental Organizations
  • 7. Outlook on Current Developments Regarding Victims
  • 8. Victims of Crime and International Law
  • 1. The Many Forms of Violence against Children
  • 2. The Impact of Violence on Children
  • 3. States' Obligations to Prevent VAC and Protect Child Victims
  • 4. Improving the Prevention of Violence against Children
  • 5. Improving the Criminal Justice Response to VAC
  • 6. Addressing Violence against Children within the Justice System
  • 1. The Role of the Justice System
  • 2. Convention on the Rights of the Child & International Legal Framework on Children's Rights
  • 3. Justice for Children
  • 4. Justice for Children in Conflict with the Law
  • 5. Realizing Justice for Children
  • 1a. Judicial Independence as Fundamental Value of Rule of Law & of Constitutionalism
  • 1b. Main Factors Aimed at Securing Judicial Independence
  • 2a. Public Prosecutors as ‘Gate Keepers’ of Criminal Justice
  • 2b. Institutional and Functional Role of Prosecutors
  • 2c. Other Factors Affecting the Role of Prosecutors
  • Basics of Computing
  • Global Connectivity and Technology Usage Trends
  • Cybercrime in Brief
  • Cybercrime Trends
  • Cybercrime Prevention
  • Offences against computer data and systems
  • Computer-related offences
  • Content-related offences
  • The Role of Cybercrime Law
  • Harmonization of Laws
  • International and Regional Instruments
  • International Human Rights and Cybercrime Law
  • Digital Evidence
  • Digital Forensics
  • Standards and Best Practices for Digital Forensics
  • Reporting Cybercrime
  • Who Conducts Cybercrime Investigations?
  • Obstacles to Cybercrime Investigations
  • Knowledge Management
  • Legal and Ethical Obligations
  • Handling of Digital Evidence
  • Digital Evidence Admissibility
  • Sovereignty and Jurisdiction
  • Formal International Cooperation Mechanisms
  • Informal International Cooperation Mechanisms
  • Data Retention, Preservation and Access
  • Challenges Relating to Extraterritorial Evidence
  • National Capacity and International Cooperation
  • Internet Governance
  • Cybersecurity Strategies: Basic Features
  • National Cybersecurity Strategies
  • International Cooperation on Cybersecurity Matters
  • Cybersecurity Posture
  • Assets, Vulnerabilities and Threats
  • Vulnerability Disclosure
  • Cybersecurity Measures and Usability
  • Situational Crime Prevention
  • Incident Detection, Response, Recovery & Preparedness
  • Privacy: What it is and Why it is Important
  • Privacy and Security
  • Cybercrime that Compromises Privacy
  • Data Protection Legislation
  • Data Breach Notification Laws
  • Enforcement of Privacy and Data Protection Laws
  • Intellectual Property: What it is
  • Types of Intellectual Property
  • Causes for Cyber-Enabled Copyright & Trademark Offences
  • Protection & Prevention Efforts
  • Online Child Sexual Exploitation and Abuse
  • Cyberstalking and Cyberharassment
  • Cyberbullying
  • Gender-Based Interpersonal Cybercrime
  • Interpersonal Cybercrime Prevention
  • Cyber Organized Crime: What is it?
  • Conceptualizing Organized Crime & Defining Actors Involved
  • Criminal Groups Engaging in Cyber Organized Crime
  • Cyber Organized Crime Activities
  • Preventing & Countering Cyber Organized Crime
  • Cyberespionage
  • Cyberterrorism
  • Cyberwarfare
  • Information Warfare, Disinformation & Electoral Fraud
  • Responses to Cyberinterventions
  • Framing the Issue of Firearms
  • Direct Impact of Firearms
  • Indirect Impacts of Firearms on States or Communities
  • International and National Responses
  • Typology and Classification of Firearms
  • Common Firearms Types
  • 'Other' Types of Firearms
  • Parts and Components
  • History of the Legitimate Arms Market
  • Need for a Legitimate Market
  • Key Actors in the Legitimate Market
  • Authorized & Unauthorized Arms Transfers
  • Illegal Firearms in Social, Cultural & Political Context
  • Supply, Demand & Criminal Motivations
  • Larger Scale Firearms Trafficking Activities
  • Smaller Scale Trafficking Activities
  • Sources of Illicit Firearms
  • Consequences of Illicit Markets
  • International Public Law & Transnational Law
  • International Instruments with Global Outreach
  • Commonalities, Differences & Complementarity between Global Instruments
  • Tools to Support Implementation of Global Instruments
  • Other United Nations Processes
  • The Sustainable Development Goals
  • Multilateral & Regional Instruments
  • Scope of National Firearms Regulations
  • National Firearms Strategies & Action Plans
  • Harmonization of National Legislation with International Firearms Instruments
  • Assistance for Development of National Firearms Legislation
  • Firearms Trafficking as a Cross-Cutting Element
  • Organized Crime and Organized Criminal Groups
  • Criminal Gangs
  • Terrorist Groups
  • Interconnections between Organized Criminal Groups & Terrorist Groups
  • Gangs - Organized Crime & Terrorism: An Evolving Continuum
  • International Response
  • International and National Legal Framework
  • Firearms Related Offences
  • Role of Law Enforcement
  • Firearms as Evidence
  • Use of Special Investigative Techniques
  • International Cooperation and Information Exchange
  • Prosecution and Adjudication of Firearms Trafficking
  • Teaching Methods & Principles
  • Ethical Learning Environments
  • Overview of Modules
  • Module Adaption & Design Guidelines
  • Table of Exercises
  • Basic Terms
  • Forms of Gender Discrimination
  • Ethics of Care
  • Case Studies for Professional Ethics
  • Case Studies for Role Morality
  • Additional Exercises
  • Defining Organized Crime
  • Definition in Convention
  • Similarities & Differences
  • Activities, Organization, Composition
  • Thinking Critically Through Fiction
  • Excerpts of Legislation
  • Research & Independent Study Questions
  • Legal Definitions of Organized Crimes
  • Criminal Association
  • Definitions in the Organized Crime Convention
  • Criminal Organizations and Enterprise Laws
  • Enabling Offence: Obstruction of Justice
  • Drug Trafficking
  • Wildlife & Forest Crime
  • Counterfeit Products Trafficking
  • Falsified Medical Products
  • Trafficking in Cultural Property
  • Trafficking in Persons
  • Case Studies & Exercises
  • Extortion Racketeering
  • Loansharking
  • Links to Corruption
  • Bribery versus Extortion
  • Money-Laundering
  • Liability of Legal Persons
  • How much Organized Crime is there?
  • Alternative Ways for Measuring
  • Measuring Product Markets
  • Risk Assessment
  • Key Concepts of Risk Assessment
  • Risk Assessment of Organized Crime Groups
  • Risk Assessment of Product Markets
  • Risk Assessment in Practice
  • Positivism: Environmental Influences
  • Classical: Pain-Pleasure Decisions
  • Structural Factors
  • Ethical Perspective
  • Crime Causes & Facilitating Factors
  • Models and Structure
  • Hierarchical Model
  • Local, Cultural Model
  • Enterprise or Business Model
  • Groups vs Activities
  • Networked Structure
  • Jurisdiction
  • Investigators of Organized Crime
  • Controlled Deliveries
  • Physical & Electronic Surveillance
  • Undercover Operations
  • Financial Analysis
  • Use of Informants
  • Rights of Victims & Witnesses
  • Role of Prosecutors
  • Adversarial vs Inquisitorial Legal Systems
  • Mitigating Punishment
  • Granting Immunity from Prosecution
  • Witness Protection
  • Aggravating & Mitigating Factors
  • Sentencing Options
  • Alternatives to Imprisonment
  • Death Penalty & Organized Crime
  • Backgrounds of Convicted Offenders
  • Confiscation
  • Confiscation in Practice
  • Mutual Legal Assistance (MLA)
  • Extradition
  • Transfer of Criminal Proceedings
  • Transfer of Sentenced Persons
  • Module 12: Prevention of Organized Crime
  • Adoption of Organized Crime Convention
  • Historical Context
  • Features of the Convention
  • Related international instruments
  • Conference of the Parties
  • Roles of Participants
  • Structure and Flow
  • Recommended Topics
  • Background Materials
  • What is Sex / Gender / Intersectionality?
  • Knowledge about Gender in Organized Crime
  • Gender and Organized Crime
  • Gender and Different Types of Organized Crime
  • Definitions and Terminology
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Module 8: Criminal Justice Response

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E4J University Module Series: Firearms

Introduction and learning outcomes.

  • International and national legal framework
  • Firearms related offences
  • Role of law enforcement

Firearms as evidence

  • Use of special investigative techniques
  • International cooperation and information exchange
  • Prosecution and adjudication of firearms trafficking

Possible class structure

Core reading, advanced reading, student assessment, additional teaching tools.

  • First published in April 2020

  This module is a resource for lecturers  

Firearms and ballistic marching play an important role in criminal investigations, as “ every firearm tells a story ”. The information required to depict their story can be obtained from both the exterior and interior of a firearm, or from ammunition, and can be used to further investigations and prosecutions which contribute to intelligence gathering and analysis.

Firearms and their surrounding area at a crime scene can furnish a variety of evidence. These crime scenes can include, but are not limited to any place where:

  • A victim has sustained a firearms-related injury;
  • A firearm has been criminally discharged;
  • A firearm/firearm parts or components/ammunition/ammunition components believed to have been used in or linked to a crime is discovered; and
  • A firearm/firearm parts or components/ammunition has been unlawfully manufactured, converted, or test fired.

A ‘ crime gun ’ is a firearm that is possessed unlawfully and/or has been used in the commission of a crime. Proper examination and tracing (see below) of these items may:

  • Confirm/eliminate the weapon as the source of shots fired during the commission of a crime;
  • Enable the identification of persons of interest;
  • Reveal links to related crimes;
  • Indicate evidence of an illicit trafficking network; or
  • Indicate evidence of illicit manufacturing. 

Firearms-related evidence can be used both in relation to the main crime but can also lead to the building of strong parallel criminal cases, such as international firearms trafficking. Sometimes, one piece of evidence can help in both investigations. For example, a ballistic comparison can confirm that a firearm was used in a murder case but also in other crimes committed in another country, which is already an indicator of the routing of that firearm.

Too often, the value of evidence that firearms, ballistics and ammunition provide is overlooked in criminal investigations; enforcement operations stop at the point of seizure or recovery. Yet, seized and recovered firearm-related items may themselves provide critical evidence of a broad range of additional crimes, such as firearms trafficking and illicit manufacturing. 

Firearms chain of custody

Ensuring the chronological and careful documentation of evidence relating to a crime scene, or alleged crime, is vital; this is known as the ‘ chain-of-custody ’. If during the investigation, steps are taken to ensure ‘ traceability and continuity ’ of the evidence for the duration of the investigation from crime scene to courtroom, it is possible to establish its connection to an alleged crime (UNODC, 2009). It is important to preserve the value of any evidence that is collected during an investigation. The chain-of-custody can present a significant opportunity for error if it is not maintained correctly (UNODC, 2009).

Health and safety procedures are of paramount importance when arriving at crime scenes and should remain a priority throughout the process, to ensure the safety of officers and others present. Accordingly, crime scene examinations must be undertaken with the support, guidance and supervision of suitably trained firearms and other experts, and/or forensic firearms experts, who can help ensure all activity is safe while not compromising potential forensic evidence.

Firearm identification

Firearms identification , as detailed in Module 2, is a fundamental step in firearms trafficking investigations because it provides the essential elements for the unique identification and tracing of the firearm.

There are at least five key identifiers of a firearm: the make , model , calibre , manufacturer, and serial number. Other markings (import or proof house markings), the year of manufacture or import, as well as additional specific characteristics, may contribute to its identification.

Firearms identification can sometimes be challenging because of the large variety of firearms producers, makes and models. Sometimes, the same producer may manufacture different models of firearms with the same serial number. However, when adding the make, model and calibre to the serial number, it will be possible to uniquely identify and distinguish one firearm from another.

A further challenge in the identification of firearms refers to the manufacturer or make, as there are many firearms that are produced under licence by various countries. For example, the AK-47 is one of the firearms posing serious challenges to proper identification because of the similarities encountered between firearms produced by various manufacturers. It is estimated that more than 75 million AK-type firearms have been manufactured since the original AK-47 first entered service in the Soviet Union in 1949. Today, there are in excess of 30 varieties of Kalashnikov assault rifle, most retaining the distinctive banana-shaped ammunition clip, which are frequently misidentified as AK-47 rifles. Figure 8.5 shows several variants of AK-47 and some of the details that make the difference during the identification process (Small Arms Survey Weapons ID Database).

The firearms identification characteristics and tools are addressed in Module 2 on firearms.

technology and firearm evidence presentation

Figure 8.5AK-47 variants and distinguishing features ( Small Arms Survey, The Weapons ID Database , 2018)

Firearms examiners can use various tools designed to help them correctly identify a firearm, ranging from manufacturers identification tools to specialized databases. The best-known database used for firearm identification is the INTERPOL Firearms Reference Table (FRT), which is an online interactive tool used to provide a standardized methodology to identify and describe firearms (INTERPOL, 2018a).

In addition to firearm identification, the examiners need to assess the functionality of the firearm, mainly considering the following aspects:

  • Whether the firearm is capable of firing live ammunition;
  • Whether the firearm has undergone functional modifications (for example if it was modified from semiautomatic to automatic, or if a gas firearm was modified to discharge real bullets);
  • Whether a firearm has been deactivated or reactivated;
  • Whether the firearm may be subject to mechanical malfunctions (for example if it can accidentally discharge).

Serial Number Restoration

Sometimes, firearms used in crimes have the serial numbers obliterated or modified in an attempt to make tracing them very difficult, if not impossible. A firearm and tool mark examiner may perform a serial number restoration if this number has been obliterated through means such as filing, grinding, or peening.

The most used methods for serial number restoration are the magnetic particle method, chemical etching, the electrolytic method, and heat treatment.

technology and firearm evidence presentation

Figure 8.6 Example of an obliterated serial number on a firearm, before restoration (Courtesy of the Association of Firearm and Tool Mark Examiners)

technology and firearm evidence presentation

Figure 8.7 Example of an obliterated serial number on a firearm, after restoration (Courtesy of the Association of Firearm and Tool Mark Examiners)

Firearm tracing.

‘ Firearms tracing ’ is a critical tool in the investigation of firearms-related offences, particularly those involving trafficking and distribution. It assists in identifying sources of firearms used by criminal organizations and terrorist groups, as well as providing valuable intelligence on methodologies utilized in the trafficking of these firearms. Firearms tracing can also provide evidence which may link a suspect to a firearm. 

The Firearms Protocol (UNODC, 2001: 3) defines tracing as “ the systematic tracking of firearms and, where possible, their parts and components and ammunition from manufacturer to purchaser for the purpose of assisting the competent authorities of States Parties in detecting, investigating and analysing illicit manufacturing and illicit trafficking .”

A successful firearms trace will identify the manufacturer and the first retail purchaser of the firearm, using the manufacturer’s records of sale. Where the firearm has been later sold by the first purchaser, tracing the weapon through the history of its distribution chain may also, subject to national laws and recordkeeping, reveal any subsequent ownership and thereby identify its current legal owner. This identified individual (or entity) may be the perpetrator of a crime or may be otherwise relevant to the case or have information to contribute about the circumstances of the crime or its perpetrator. The tracing process may thus lead to evidence that is decisive in solving or prosecuting a case.

A firearm trace is not an indication that the person of interest has committed an unlawful act; it is simply intended to provide an avenue of information for investigative fact-gathering.  In many cases additional investigation will be required to determine the point when the firearm became the subject of the investigation or inquiry, or when it became illicit.

Firearm tracing is a key resource, not only for the development of leads in a criminal investigation, but also for the development of actionable intelligence on complex firearm-related crime and firearms trafficking. The mapping and analysis of national and international firearm trace data may help to:

  • Delineate potential patterns and trends in firearm trafficking;
  • Reveal individuals and entities involved in firearm trafficking activities; and
  • Expose ‘ red flag ’ data such as disproportionate numbers of ‘ lost ’ or ‘ stolen ’ firearms from a single source, or short ‘ time-to-crime ’, etc.

The Modular Small-Arms-Control Implementation Compendium (MOSAIC 05.31, ‘ Tracing illicit small arms and light weapons ’) provides good practice and guidance on the steps for undertaking domestic and international tracing action, including the steps necessary to make and respond to international tracing requests as follows:

  • Unique identification of the weapon based on its markings and physical characteristics;
  • A domestic tracing operation to establish whether the weapon 
became illicit while under the jurisdiction of the State that recovered it (e.g. following its domestic manufacture or import), or possibly entered the country by illicit means;
  • An international tracing operation, if the weapon is suspected of having entered the country by illicit means;
  • The tracing operation (domestic or international) to identify the point in time and space at which the weapon became illicit;
  • Action taken to prosecute those responsible for diverting the weapon and to prevent similar diversions from recurring.

Firearms tracing can take place in different moments and contexts of a criminal investigation. It can be part of the initial investigative process of a law enforcement official or can also be requested by a prosecutor as part of a follow up or parallel investigation into illicit trafficking.

By implementing the tracing activities, investigators can make use of various tools available at a national level (for example, national databases on firearms owners, manufacturers, importers, and dealers) and an international level (for example, iArms and eTrace).

Tools to support international tracing of firearms

Illicit arms records and tracing management system (iarms).

INTERPOL’s Illicit Arms Records and Tracing Management System (iARMS) is the only global law enforcement platform for recording international illicit firearms. It is atool for facilitating information exchange, assisting with investigative efforts and cooperating between different criminal justice agents, and it focuses on the international movement of illicit firearms, as well as licit firearms that havebeen involved in the commission of a crime (INTERPOL, 2018c).

Criminal justice agents can record data about firearms in the iARMS system and also search to see if seized weapons have been reported lost, stolen, trafficked or smuggled. This not only helps to identify where weapons have been used and have originated from but can also help to identify potential links that may occur in different parts of the world, and different trafficking/smuggling routes (INTERPOL, 2018c).

iARMS firearms tracing relies on the close cooperation of international law enforcement, and customs and border control agencies. INTERPOL has been identified as a key partner in the implementation of firearm tracing activities by the 2005 International Tracing Instrument (INTERPOL, 2018c). ‘ Analysis of iARMS data and statistics has already significantly informed detailed assessments of the illicit flows of weapons to terrorist organizations, organized criminal groups and other unauthorized users ’ (INTERPOL, 2018c).

Introduced in 2005, the eTrace system is a law enforcement-focused firearm tracing system operated by the United States Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) National Firearms Tracing Center (NTC). eTrace supports users in submitting, retrieving, storing, and querying firearms trace-related information. Registered users can initiate a search on virtually any data field or combination of data elements, such as firearms serial numbers, an individual’s name, type of crime, date of recovery, or other identifiers.

Consistent with the ATF mandate to prevent and fight violent crime, weapons of interest for eTrace purposes are restricted to US-manufactured and US-imported firearms that have been recovered from a crime scene. Access to the web-based service (currently available in both English and Spanish user interfaces) is limited to US and foreign government law enforcement agencies in connection with, and for use in, a criminal investigation or prosecution, and to US federal agencies for national security or intelligence purposes. Requests to the ATF to trace firearms can be submitted by any domestic or foreign law enforcement agency, although foreign agencies are required to have a Memorandum of Understanding with the ATF in order to receive this support.

Ballistic analysis and comparison

Unsurprisingly, spent bullets and cartridge cases are much more likely to be found at the scene of a violent crime than the gun itself. An essential line of inquiry from this evidence is to identify the firearm, or the type of firearm, that fired them.

The science that deals with the scientific analysis of fired ammunition is called Ballistic Analysis, or simply Ballistics, which Oxford Dictionaries Online define as “ the science of projectiles and firearms ” or “ the scientific study of the effects of being fired on a bullet, cartridge or gun .”

The UN Firearms Protocol defines “ Ammunition ” as “ the complete round or its components, including cartridge cases, primers, propellant powder, bullets or projectiles, that are used in a firearm…. ” (UNODC, 2001: 2-3). A bullet is an item within a single round of ammunition.

Ballistics is divided in three subcategories:

  • Internal ballistics, which deals with the ejection of the projectile from the firearm;
  • External ballistics, which deals with the flight of the projectile through the air; and
  • Terminal/wound ballistics, which deals with the impact of the projectile on a target.

The examination of individual and class characteristics of a spent bullet, spent cartridge or firing residues recovered from a crime scene can help classify the ammunition (make, calibre or gauge), trace the ammunition, establish the bullet trajectory, identify the shooting firearm, and establish links between the firearm and other crimes. It can also identify the shooter or establish the location of a firearm.

For example:

  • Plastic wadding can help identify the gauge of a firearm used and the make/type of cartridge fired, as well as identify whether a shotgun was shortened;
  • Fibre wadding can help identify the gauge of a firearm used;
  • A shotgun shot can help identify the type of cartridge used;
  • A spent shotgun cartridge can provide important details of the firearm used, as well as potential links to other crimes; 
  • Bullet/bullet fragments can provide details of the firearm used, as well as potential links to other crimes;
  • Gunpowder residues can help identify the shooter, or the location where a firearm was used;
  • Termination marks can help identify the location of the shooter and the trajectory of the projectile;
  • Spent bullet cartridge cases can provide important details of the firearm used, as well as links to other crimes; and
  • Microstamping on bullets or firing pins can help identify the manufacturer of the used firearm or ammunition;
  • The colour of a bullet tip can reveal the type of bullet and its country of manufacture.

One important part of the ballistic examination is the ballistic comparison. As with fingerprints, every firearm has unique characteristics. The barrel of a weapon leaves distinct markings on a projectile. The breech mechanism also leaves distinct markings on the cartridge case. These markings are produced by the breech face itself, the firing pin, extractor, and ejector. By comparing these unique markings, the examiner can provide information that can help identify the firearm used in the shooting, whether two or more rounds were fired with the same firearms, and further connect the firearm with other crimes.

technology and firearm evidence presentation

Figure 8.8 Microscopic comparison of a fragment of a bullet jacket (left) and a test fired bullet from a suspect firearm (right) (Courtesy of US NIST)

technology and firearm evidence presentation

Figure 8.9 Two test-fired cartridge cases from the same firearm compared side-by-side with a comparison microscope (Source: Bunch et al . (2009) under Fair Use Policy )

Ballistic comparison is a relatively new technology that has been developed by few companies. In technical terms, the two basic tools for ballistic investigations are the comparison microscope, which allows comparison and effective analysis of the evidence, and a software program that allows for the ballistic comparison using a system which stores the data and image base of firearms for further comparison in order to identify relationships between criminal acts.

The most well-known systems on the market are the Integrated Ballistic Identification System (IBIS) , and its Ballistic Information Network (IBIN), ALIAS , ARSENAL and EVOFINDER .

In recent times, more countries have started to develop their own domestic systems, based on one of the above described major technologies (for example, SUCOBA in Colombia based on IBIS technology).

Matching ballistic information is one of the key measures in the fight against the misuse of firearms, and it has uncovered numerous connections between firearm-related crime scenes in different countries ( INTERPOL, 2018b ). It allows police to develop new investigative leads based on ballistics cross-comparison, and to find connections between separate crime scenes from different countries that could have otherwise remained undetected (INTERPOL, 2018b).

Next: Use of special investigative techniques

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Center for Statistics and Applications in Forensic Evidence

CSAFE Develops New Bullet Matching Technology

technology and firearm evidence presentation

  • Posted August 29, 2017

The Center for Statistics and Applications in Forensic Evidence (CSAFE) is creating innovative solutions to the lack of scientific foundations in firearms examination.  Firearms examiners are charged with providing accurate assessments of bullet evidence, despite limitations in current analysis techniques. Current best practice relies on a subjective visual inspection of bullets and cartridge cases to determine if a particular gun was used at a crime scene.  Due to potential human error and bias, this methodology decreases confidence in results when used in courtroom testimony.

CSAFE researcher Dr. Heike Hofmann, Professor of Statistics at Iowa State University, and contributing researcher Dr. Eric Hare have developed a groundbreaking new method of bullet comparison.  The CSAFE researchers’ new bullet matching technology uses a fully automated statistical algorithm model to predict the probability of a match of two unknown pairs of bullets.

In response to the need for continuous improvement in the process of bullet comparison, Hofmann said, “We want to get away from language of ‘this is a match’ and ‘this is not a match’ and move towards a matching score that allows us to assess the quality of evidence on a continuum.”

Hofmann acknowledges that in some cases, matches are very convincing where everyone who examines the bullets agrees.  “Then there’s those cases in-between where different forensic examiners might come to different conclusions,” she said.

Hare and Hofmann worked in collaboration with the National Institute of Standards and technology (NIST) to develop the algorithm utilizing the NIST ballistic toolmark database of 3D bullet scans. Researchers initially identify signature features or a combination of features on each bullet that carry the most information.  The algorithm then numerically computes differences, enabling discrimination across samples.

Hofmann said, “The idea is that when you’ve got an automatic approach that you get a number at the end and that process is repeatable. So if you get the same input, use the same parameters, then you will always get the same results.”

Hofmann’s goal is to provide a quantitative assessment of the association of two bullets through a signature-based score, thus reducing human error.  “You’re taking the human being a little bit out of the loop, and the matching becomes less subjective and moves into a more objective realm,” she said.

Public Access Increases Transparency

CSAFE researchers are breaking with tradition by publishing technology that is accessible to everyone through an open model.  Hofmann and Hare’s algorithm can be found in their R package “bulletr”, which is publicly available on GitHub.

Hofmann said, “I totally believe in openness and transparency.  I want to have transparent algorithms that can be peer reviewed and checked. I want to have open data so other people can have access to the same kind of information.”

At present, a suspect accused of a crime has no opportunity to review the results of firearm analysis beyond the 2D images of the crime scene and questioned samples.  CSAFE’s new technology is user friendly enough that experts on both sides in a trial can carry out their own analysis of the data.

“We are implementing new features so they are accessible to everyone, not just a selected group,” Hofmann said.

This technology can also be used to assist juries in determining the strength of a match between bullets.  With an automated algorithm model, examiners are able express a degree of uncertainty in their conclusions.

If the score from the algorithm is not as high as is seen in other known matches, the examiner has a way of saying that he or she feels that it could still be a match, but that the analysis is not 100 percent conclusive.  A jury is able to see the score and determine if there is a measure of doubt in the results, thus protecting against wrongful convictions.

Future Collaborations Aim to Engage Practitioners in the Process

CSAFE researchers have already developed many collaborating partnerships in an effort to expand the reach of their technology and include practitioners in the conversation.

In order to continue creating objective and repeatable methods of bullet comparison, Hofmann and her team are designing a large-scale experiment in collaboration with the Story County Sheriff’s Office and the Defense Forensic Science Center.

The goal of the experiment is to continue expanding the database of processed bullets, and advance the development of the open source R package “bulletr.”

With a team based approach to research and commitment to learning from practitioners, CSAFE will continue to advance firearm examination technology with real-world applications.


Upcoming AAAS Conference will Explore Issues Related to Scientific Evidence in the Courts

Upcoming AAAS Conference will Explore Issues Related to Scientific Evidence in the Courts

NIST will Host a Workshop on the Scientific Foundation Review of Footwear Impression Examination

NIST will Host a Workshop on the Scientific Foundation Review of Footwear Impression Examination

NIST Finalizes Report of Forensic Bitemark Analysis

NIST Finalizes Report of Forensic Bitemark Analysis

Recent news, csafe learning announces two upcoming live webinars and new on-demand stats starters, csafe will exhibit and present at the 2024 aafs conference, csafe researchers contribute to pnas special feature on science, evidence, law, and justice, applications open for csafe's 2024 summer research program for undergraduates.

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Firearms 3D technology: Advantages and Value for Implementing 3D Technologies

This presentation will demonstrate the effectiveness of integrating 3D technology into the forensic firearms/toolmarks discipline and the decision analysis used for selecting samples for virtual comparison.  In 2009, a report by the National Academy of Sciences (“Strengthening Forensic Science in the United States: A Path Forward”) called into question, amongst other issues, the objectivity of visual toolmark identification (note that firearms identification is considered to be a subset of toolmark identification). The National Academies recommended development of objective toolmark identification criteria and error rate estimates.

Currently in the forensic science community of toolmark identification, there are no objective standards for identification. In recent years, instruments have emerged with the capability to measure toolmark topographies and incorporate matching algorithms that have the potential to provide objective support for an examiner’s conclusion. In 2012, the FBI Laboratory’s Firearms/Toolmarks Unit (FTU) set forth with an approach aimed at addressing the recommendations identified in the NAS Report to evaluate the possibility of supplementing traditional light comparison microscopy with three-dimensional topographic measurement data. The FBI Laboratory had another goal: to determine the reliability of available algorithms to generate a score for match criteria and started acquiring instruments for this endeavor.

In 2014, the FBI Laboratory acquired the Cadre® Forensic TopMatch- GelSight instrument which uses the Bidirectional Reflectance Distribution Function to acquire 3D surface images and allows for side-by-side evaluation of surface topographies with a matching algorithm search capability for topography similarities.  In October of 2017, the FTU completed its validation studies and established acceptable operating parameters for the Cadre® Forensic TopMatch- GelSight instrument and went live for casework to supplement light comparison microscopy for the examination of ammunition components. This presentation will cover highlights of the process, including the Standard Operating Procedures put in place, the laboratory workflow, selection of casework, blind verification incorporation, reexamination of casework using light microscopy and Daubert preparation. 

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Introduction to Forensic Science and Criminology

Module 4 – forensic examination and firearms evidence, forensic examination and firearms evidence, the forensic examination.

The firearm examiner must be familiar with all the necessary information and knowledge about the nature of firearms and their components in order that they may understand and appreciate every piece of information that is very essential in establishing proof about the case or problem.

If we were asked to give significance about what things must be given importance, the following must be taken into consideration by a forensic examiner in order to arrive at more credible conclusions pertaining to firearms examinations:


Barrels used for firearms manufacturing are made up of a solid piece of metal. Metal for this purpose is carefully selected for its chemical and metallurgical structure in order to assure high-quality products after several machine operations and heat treatment. In the process of barrel production by means of  “drilling”, a rough hole of uniform diameter is produced on the selected metal thus producing several scars and scratches on its interior surface that becomes permanent.

technology and firearm evidence presentation

The same is produced when a firearm is being rifled (producing rifling). Whatever polishing and finishing efforts of the manufacturer to make its surface clear, said scratches and scars remain permanent and cannot be completely removed. Such scars and imperfections become individual characteristics of that firearm.

technology and firearm evidence presentation


A nother face of firearms needed and important in firearm identification is the production and finish of the breechface. This is the very portion of the gun that strikes the cartridge case and the primer is forced backward when a cartridge is fired in the chamber. During the process, breechface marks will be imprinted at the primer and base of the cartridge case that will serve as an important identification for a particular firearm.

technology and firearm evidence presentation

Both barrel and firearms slides produce several marks on bullets and spent shells that can be subjected to forensic analysis. This is what FIREARM IDENTIFICATION is doing one of the branches of toolmark identification. This is because the firearm, made of a material harder than the ammunition components, acts as a tool that leaves impressed or striated marks on the various shell casings and other ammunition components with which it comes into contact.

And like fingerprints, no two firearms, even those of the same make and model, will produce the same marks on fired bullets and cartridge cases. Furthermore, the manufacturing processes and the use of the firearm leave surface characteristics that cannot be exactly reproduced in any other firearm. This means that the toolmarks are unique to each firearm.

Another aspect that people often don’t know, is that firearms do not normally change much over time. This allows for firearms recovered months or even years after a shooting to be identified by forensic experts as having fired a specific bullet or cartridge case.


RIFLING MARKS – they are found on the cylindrical portion of the fired bullets or slugs and are caused by the riflings inside the barrel. These marks are specifically classified as “Land marks” and “Groove marks”; (1)

technology and firearm evidence presentation

SKID MARKS – are-generally found on bullets on slugs fired from revolvers, These marks are more or less found on the anterior portion of the fired bullets or slugs, and are caused by the forward movement of the build before it rotates as required by riflings;

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STRIPPING MARKS – are generally found on bullets or slugs through loose fit” barrels wherein the riflings are badly worn out.

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Other notable characteristics that may be noticed in a form of microscopic marks that has value or “ no value at all ” as far as firearms examination are concerned are the following:

SHAVING (Shearing) is the cutting of metal from the surface of a bullet due to  cylinder  misalignment in a revolver. A large amount of shaving may leave a void in the bearing surface of a bullet, which may not receive rifling impressions.

A SLIPPAGE is another term used for SKID MARKS. This is formed on the bearing surface of bullets as they enter the rifling of the barrel before the bullet engages the rifling.

FLARED BASES of bullets fired from short-barreled handguns or bullets with deep base cavities are subject to expansion after leaving the barrel of a firearm. Measuring a flared base would be misleading; the better-protected base normally provides the best dimensional data.

BLOWBY is the escaping of gases past a fired bullet while the bullet is still in the barrel. These high-pressure gases are at a very high temperature and can melt or etch the bearing surface of plain lead bullets. As a result, the width of rifling impressions can be seriously degraded and appear very blurry and indistinct.


There are two types of marks that can be found in any fired shell on any type of firearm. The IMPRESSED ACTION MARKS and the STRIATED ACTION MARKS .


With a few exceptions, these are produced when a cartridge case is fired in a firearm.  The two most common impressed action marks are firing pin impressions  and  breech marks .   Impressed toolmarks (also called compression or indentation marks ) are produced when a tool is placed against another object and sufficient force is applied to the tool to leave an impression. These impressions are contour variations left on the surface of the object by this interaction.

Notably, added to the two are ejector marks which are also striated action marks. 

The Firing Pin Impressions . These are indentations created when the firing pin of a firearm strikes the primer of a centerfire cartridge case or the rim of a rimfire cartridge case.   If the nose of the firing pin has manufacturing imperfections or damage, these potentially unique characteristics can be impressed into the metal of the primer or the rim of the cartridge case. (Below is an example of firing pin marks on rimfire shells on the left and centerfire shell on the right)

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The Breech Marks.  By far the most common impressed action marks on cartridge cases are  breech marks .  Most fired cartridge cases are identified as having been fired by a specific firearm through the identification of breech marks.

Very high pressures are generated within a firearm when a cartridge is discharged.  These pressures force the bullet from the cartridge case and down the barrel at very high velocities.  When a firearm is discharged, the shooter will feel the firearm jump rearward.  This rearward movement of the firearm is called  recoil .  Recoil is for the most part caused by the cartridge case moving rearward as an opposite reaction to the pressures generated to force the bullet down the barrel.

When the head or base of the cartridge case moves rearward, it strikes what is called the  breech face of the firearm. 

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The Ejector Marks. Ejector marks are sometimes created when cartridges or cartridge cases are ejected from the action of a firearm.  Ejector marks can be either striated or impressed, but the impressed ejector marks not only can be used to identify a cartridge case as having passed through a firearm’s action they can also be an indication that the cartridge case was fired in the firearm.  Ejector marks like those seen below could only be reproduced when the cartridge cases were fired in the firearm and not by simply hand chambering and ejecting a live cartridge.

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S triated action marks are common to cartridge cases that have passed through the action of an auto-loading or repeating firearm.   Striated action marks can be produced on cartridge cases by contact with a number of different areas within the firearm.  Some of the more common striated action marks include chamber marks; shear marks, firing pin drag marks, extractor marks, and ejector marks.

The Chamber Marks. Roughness in the chamber of a firearm can scratch the outer walls of a cartridge case when loaded and removed from the chamber. Most chamber marks occur after the cartridge is fired.  Cartridge cases expand when fired pressing out against the walls of the chamber.  When they are pulled out of the chamber, the sides of the cartridge case can be scratched.

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Chamber marks appearing on a fired shell can be any of the following:

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The Shear Marks. When a cartridge case is forced backward from recoil the primer embeds itself in the firing pin hole.  As the slide of the pistol starts to recoil, the barrel will drop slightly as the action opens.  The dropping barrel forces the cartridge case to move down slightly and when this happens the lower edge of the embedded primer is sheared downward and out of the firing pin hole. An illustration below shows the production of shear marks on the head of the cartridge case just along the side of the firing pin marks. Shears surround the opening of the firing pin hole.

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The Extractor Marks. Another action mark, usually found in striated forms is those created by the extractor  of most auto-loading or repeating firearms.   The extractor is a small part sometimes resembling a hook that is used to remove a cartridge or cartridge case from the chamber of a firearm.  The image below shows the extractor of a 9mm GLOCK pistol hooked into the extractor groove of a cartridge.  As the slide of the pistol moves to the rear, the extractor pulls the cartridge case along with it until it is ejected from the pistol.

The Magazine Lip Marks.  T hese markings are found near the rim of the cartridge cases and are caused by magazine lips during the loading of the cartridges into the position of firing. 

Firing Pin Drag Marks.  In a similar process, striated marks called firing pin drag marks can be produced.  When the firing pin springs forward to strike the primer of a cartridge, it may remain slightly forward and embedded in the primer.  Certain barrels (like in the GLOCK) drop down slightly as recoil is forcing the action open.  The cartridge case drops with the barrel causing the nose of the protruding firing pin to drag across the primer as it leaves the firing pin impression.  The below comparison image shows firing pin drag marks produced by a Colt 45 AUTO pistol .

The Ejector Mark. (See our explanation in the impressed action marks above)

The summary of the marks that can be found on the shell is illustrated below:

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We need to remember that some of the marks may occur only when the firearms are in action and during the time firearms are fired. Such action will produce force and pressure that is enough to produce both striated and impressed action marks.

Consequently, the final identification of a fatal gun is based not upon a few markings, but upon a PATTERN OF MARKINGS, (the peculiarities of markings of particular firearms alleged to have been used in the commission of a crime). These markings are the signature of a particular firearm and will serve and remain as their permanent identification.


Firearm Identification is a comparative science that applies a two-level approach, using class characteristics and individual characteristics.


Class characteristics of firearm barrels include measurable features which are part of the design of the firearm, such as the caliber and rifling pattern.

The caliber of a bullet is, at its most basic definition , the diameter of the bullet . The diameter can be expressed in inches or in millimeters. The diameter of the bullet will correspond to the diameter of the barrel of the firearm. The caliber designation of the firearm or ammunition depends not only on the diameter of the bullet but also on other dimensions of the cartridge, such as length and shape.

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Rifling is a pattern of channels that run the length of a firearm barrel, manufactured with a helical pattern, or twist. These raised and lowered areas are called lands and grooves. The purpose of rifling is to impart a spin on the bullet along its long axis, which gyroscopically stabilizes the projectile and allows it to travel more accurately.  The number and width of lands and grooves are determined by the manufacturer and will be the same for a large group of firearms.

This allows for quick inclusion or exclusion of a firearm as a possible weapon in a given case:   If the bullet recovered from a crime scene has rifling of five lands and grooves with a right twist, and a suspect firearm submitted by the police agency has six lands and grooves with a left twist, the examiner knows immediately that the bullet was not fired by that particular firearm.   The same kind of exclusion or elimination can be made if the rifling pattern has the same twist but different widths: wide lands and skinny grooves vs. wide grooves and skinny lands, for example.

Looking at the list below will help us what are CLASS CHARACTERISTICS: CLASS CHARACTERISTICS are those that exist in a firearm or firearms even prior to their manufacture. These characteristics are factory specifications and they serve as a basis to identify a group or class of firearms, like the following:

[1] Bore diameter – this is the distance measured between two opposite land and is considered as the caliber of the firearm.

[2] Number of lands and grooves – the number of land and grooves inside the bore of a fired firearm is always the same. If a bore has six lands, it will also have six grooves. The number of lands and grooves is a valuable class characteristic.

[3] Lands – the elevated portions inside the barrel

[4] Grooves – the depressed portions canal-like inside the barrel.

[5] Direction of twist – the rifling inside the gun barrel may twist either to the right or left. The twist of the rifling causes the bullet to “rotate” as it passes through the bore for the bullet to have “gyroscopic stability during its flight from muzzle to target.

[6] Width of lands – land width is dependent on the bore diameter, groove width, and number. The lands are a remainder of the circumference after subtracting all the groove widths.

[7] Width of grooves – this is measured as the shortest distance between the two sides or edges of a groove.

[8] Depth of grooves – groove depth in the bore is measured on a radius of the bore as seen in the cross-section. Grooves are usually a few thousand an inch deep. It is also equal to the height of the side of the land.

[9] Pitch of riflings – it is a measure of the twisting of the land and grooves. It refers to the distance advance by riflings in one complete run (360 degrees).

Additionally, the class characteristics for a fired cartridge case include the cartridge caliber, the shape of the firing pin, and the tooling marks on the breech .

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If the class characteristics of two bullets or cartridge cases are the same, the firearm examiner moves on to the next level of comparison: individual characteristics.


Individual characteristics are those which are peculiar in a particular firearm and which are not found in all other firearms. They serve to identify a particular gun. These individual characteristics are generally found on the interior – the surface of a gun barrel, which registers into the fired bullet while inside the bore of the gun and to the base of the cartridge case when it exploded inside the chamber of the gun.

The successful identification of the firearms from discharged bullets and empty cartridge cases is based upon a basic principle “THERE IS NO DUPLICATION IN NATURE. AND EXCEPTIONS TO THIS RULE ARE NEVER MANIFESTED AS THE RESULT OF MAN’S INGENUITY. These characteristics are produced at the stage of manufacturing of firearms, and a result of the coincidental procedure and subsequent mutations.

Individual characteristics are the tiny imperfections and irregularities on the parts of a firearm produced accidentally during manufacture or from subsequent wear and tear.  When a bullet travels down the barrel of a firearm, in addition to picking up the “macro” rifling marks (class characteristic), the bullet is also imparted with a pattern of lines and scratches from the individual characteristics in that barrel.

The primer of a cartridge case is struck with a firing pin that has a particular shape (class characteristic), but the firing pin also has tiny individual characteristics that can be impressed in the metal on the primer.  Since the microscopic marks in the barrel and on the firing pin are random in nature, the pattern scratched or impressed on bullets and cartridge cases fired through one firearm will be different from the pattern of another firearm, even the same make, and model . AND THIS IS WHAT WE LOOK FOR DURING THE EXAMINATION AND ANALYSIS OF FIREARMS EVIDENCE.


PATTERN MATCHING is the process of determining whether or not the details of striated marks or impressions on two objects correspond.  Early forensic scientists and their successors, (including Calvin Goddard, Julian S. Hatcher, Gerald Burrard, J. Howard Mathews) practiced pattern matching. Today, examiners continue to rely on their extensive experience, training, and education to perform the specialized pattern identification  represented by toolmark identification.

The examiner compares the class characteristics of the two objects; if all class characteristics correspond, the examiner proceeds to compare the individual characteristics.  During the comparison of the individual characteristics, the examiner looks for repetitive marks occurring on both objects in the same location and position.  The examiner may test the tool in an effort to re-create the marks for comparison with the evidence marks .

This is a somewhat subjective process performed by the examiner. Pattern identification relies on the experience, training, and education of the examiner . The quality of training is the single most important element of the examiner’s competence and expertise. Long-term hands-on experience is gained from working side-by-side with an experienced examiner in a structured training program.


Toolmark examinations and comparisons represent the core area of study for firearm and toolmark examiners. The conceptual and practical aspects of toolmark identification provide the skills necessary for  firearms identification ; “firearm identification” is a specialized subset of toolmark identification . Toolmark identification is based on the following concept:

(a) A tool is defined as the harder of two objects which, when brought into contact with each other, results in the softer object receiving a toolmark.

(b) Tools (e.g., screwdrivers, firearms, bolt cutters, etc.) will bear unique microscopic characteristics due to the manufacturing processes they undergo and use and abuse.

(c) These characteristics will mark surfaces (e.g., locks, cut wires, fired bullets, etc.) with class and individual characteristics.

(d) These class and individual characteristics  are reproducible and identifiable with a particular tool.


1. The breech face and firing pin of every single firearm have individual microscopic individualities of their own;

2. Every firearm leaves its fingerprint or thumbprint on every cartridge it fires;

3. That, since the breech face of every weapon, has the individual distinction, the imprints of all cartridge cases fired from the sam e weapon are the same.

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(1) No two barrels are microscopically alike or identical as the internal surface of the bore or barrels all possess individual characteristics of their own;

(2) When a bullet is fired from a rifled gun barrel, riflings are engraved therein, which vary in its minute details with other firearms, even of the same type.

(3) Every barrel leaves its mark known as a “thumb mark or fingerprint” on every bullet that passes through it.

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(1) Bullet Comparison Microscope

The most important equipment for scientific firearms examination. It is used for comparing evidence shells and bullets and test shells and bullets to determine whether they are fired from the same gun or not. Bullet comparison microscope was introduced in 1925. The first person to own and use this equipment is Dr. Calvin H. Goddard, the known father of Modern Ballistics. To date, bullet comparison microscopes are used with ease and convenience because of the technology.

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What is shown is an old bullet comparison microscope where you need to peep at the eyepiece of the microscope (as with the stereoscopic microscope) to look at the minute detail of the striations and impression). The equipment below will give the examiner a direct enlarged image on the screen of the computer and will be recorded automatically and ready for printing as they wish.

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(2) Stereoscopic Microscope

It is similar to a microscope. Its only difference is that it has two eyepieces. It has the capability to examine two bullets or shells microscopically. This is very useful in the preliminary examination. Unlike bullet comparison microscope, it has no camera attachment and therefore cannot produce a photomicrograph.

(3) Onoscope

A small instrument sometimes used in examining the internal surface of the gun barrel. It has a tiny lamp at the internal portion and this is inserted inside the bore for internal examinations.

(4) Shadowgraph

Another instrument whose function is similar to a microscope. It contains a series of microscopic lenses of different magnifications that can be used in examining fired bullets or fired shells to determine their class characteristics especially for preliminary examination and orientation purposes.

(5) Caliper

An instrument used in making measurements such as bullet diameter, bore diameter, barrel length, and other important details.

(6) Helixometer

This is an instrument used in measuring the pitch of riflings.

(7) Micrometer

Have the same use as in helixometer.

(8) Analytical or Torsion Balance

This is used for determining weights of bullets or shotgun pellets for possible determination of type, caliber, and make of firearms.

(9) Bullet Recovery Box (Drum)

A box used for test firing of the suspected firearms. Other means used in the test-firing of suspected firearms to obtain test bullets or test shells for comparative purpose are the following:

(10) Magnifying Glass

Use for preliminary examination and orientation purposes of the different marks (striation) on a bullet, shell, and firearms.

(11) Taper Gauge

Used primarily for determining the bore diameter of firearms.

(12) Electric Marker

Used in the laboratory for marking fired bullets, fired shells, and firearms submitted for examination.


A thorough understanding of physical evidence, its protection, preservation, and examination are necessary if the following important duties are properly performed:

[1] Once an officer has taken evidence into his possession, he must be able to establish its chain of custody until;

= The same is presented in court;

= Or return it .to the victim or suspect, as the case may be.

[2] It is necessary to be able to establish where the evidence has been at all times:

= If the officer expects to overcome questions presented by the defense;

= And to impress the judge or court that the evidence has been properly protected.

[3] If the evidence is out of the officer’s control for any period of time, he must be able to establish:

= Who had the evidence; and

= When it was returned.

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When collecting physical evidence, the officer or investigator should collect all articles, which are or may at some future date, be something of value as evidence. These articles consist of:

(1) Any physical object, which may tend to or indicate whether or not a crime was committed;

(2) Anything which may connect some particular person with the crime or crime scene;

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(a) The lethal or fatal weapon

(b) Fired bullet or bullets.

(c) Fired cartridge case

(d) Metal fragments

(e) Broken glasses

(f) Shotgun


This is so for the purpose of:

(1) Making the introduction of exhibits in court simpler; and

(2) Being able to keep records, and remembers where, when, and what was collected, which is much better if several men have to hands the same exhibits;


The keyword is do not “MAC” the evidence:

[1] Mutilate – in no case should the evidence be mutilated in any way, such as crushing, if ever this can be avoided.

[2] Alter – in no case should the evidence be altered in any way that may change its original nature. If alterations do occur the investigator or officer should take note in his report why this happened.

[3] Contaminate – and finally, in no case should the evidence be contaminated, that is adding anything which, may change the nature of the physical evidence.


The crime scene should be sketched and photographed. Photographs of the victim should be taken and all other suitable articles like a weapon, bullets, shells, holes, and all other related evidence, before removing them.


The following are the procedure in proper packing of firearms or weapon, bullets, and shell:

[1] After marking the physical evidence. It must be wrapped surely in some soft material, It should always be placed in a suitable container to prevent any further or needless mutilation;

[2] Never, under any circumstances, place a discharged or fired bullet in clothing or pocket without first carefully wrapping it with some & protective covering.

[3] Regarding bullets, which are lodged in walls, furniture, wood trims, or even trees, extremes care must be exercised in removing this evidence. Do not attempt to dig out the evidence bullet with the knife, or ice pick; rather cut around the evidence in order not to touch it with anything that would tend to mark it.

[4] If the bullet or slug has broken up into many fragments or pieces, secure as many fragments as possible. These fragments may be fitted together which may aid in analyzing and examining it.

[5] If cartridge cases or shells are found at the crime scene, after marking them, they should be preserved as carefully as possible.

[6] If cartridge cases are found and appear loaded in a weapon, it is best to transport said weapon to the laboratory as it is, with the exception that a tag is secured to the weapon labeled, danger, loaded weapon.

[7] If for security reasons, the weapon must be unloaded, the investigator must carefully mark each cartridge and cartridge case together with the location of its origin.

[8] When a firearm is found at the scene of the crime the investigator should take note of the following pertinent facts about the firearms:

(a) Types of firearms (pistol, revolver, etc.);

(b) Make of the firearm (colt, S&W, etc.);

(c) The caliber of the firearm (cal. 22,38. etc.);

(d) Serial no. (most important);

(e) Load in the cylinder, if revolver, or load in the magazine, if pistol;

(f) Other features of significance (length of the barrel, nickel, or plated);

(g) Position of a firearm in relation to a dead body at the crime scene;

(h) Other distinct outside marks.

[9] When a bullet/bullets are found at the crime scene, the following should be noted;

(a) Type of bullet (lead or jacketed);

(b) The caliber of the bullet;

(c) Shape or form of the bullet (round nose, flat nose, etc,);

(d) Other metal or bullet fragment if any; and

(e) Relative position

[10] When shell or shell are found at the scene of the crime, the following should  be noted down;

(a) Number of the shells and order of recovery;

(b) The caliber of the shells;

(c) Trademark or brand of the shells;

(d) Relative position of the shells at the crime scene.


[1] The officer may be called to the witness stand several weeks or month later, or even years later after the commission of the crime, to identify the object he collected at the time of the offense;

[2] The officer can not completely rely on his memory because there will be many more cases that he will handle after every case;

[3] Defense counsel may require that the complete “chain and custody of evidence” be established

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[1] Use a distinctive mark in order to exclude others, such as your initials, serial numbers, or personal marks;

[2] Record the mark used together with the position of the mark;

[3] Record any serial number or other distinctive marks found on the physical evidence;

[4] If ever possible, mark the object Itself with Due Care in order to avoid any damages or alternation;

[5] Do not forget to mark the container where the physical evidence is placed, notwithstanding the marking already on the object itself;

[6] Whenever tags are used, make a corresponding entry in it and attach it accurately to the object.


The fired bullet or slug should be marked by the investigator or a police officer who recovers it with his initials nose or base as the case may be, together with the corresponding date of recovery. (see sample markings)

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Fired Shell

The initials of the recovering investigator together with the date of recovery should be made just on the inside and near the mouth with a sharp and metallic instrument.

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Any suspected firearm should be marked by the investigator or police officer who recovered it, with his initials and corresponding date, on any of the three main and separable parts, barrel, cylinder, and frame, in case of revolver and barrel, slide, frame or receiver , in case of a pistol . Of course, this is done without utter disregard for taking down the serial number of the firearm.


(a) type of firearm; 

(b) make of firearm; 

(c) serial number; 

(d) date of recovery;

(e) place of recovery;

(f) name of a victim if any; and

(g) name of the suspect


The following are don’t in marking firearm, bullet, and shell:

(1) Never use [x] as an initial for identifying mark;

(2) Do not put any identifying mark in a cylinder or peripheral surface of any bullet or slug.

(3) Do not put any identifying mark on the base of a shell;

(4) Do not put any identifying mark on any separable part of a firearm.


(1) Evidence should be properly preserved for future identification and presentation during the trial of the case;

(2) Firearm evidence must be kept in the proper place and under a proper condition so that it will be of greatest value in the prosecution of the case;

(3) Fired bullet & shell after having been marked should be wrapped in tissue paper & sealed in a box;

(4) The container should be properly labeled or marked;

(5) Each article of evidence should be placed in a separate container, and each container shall be accordingly marked for future references;

(6) Use a container that will not easily break and one which is large enough that the evidence can be removed and replace without difficulty;

(7) The suspected firearm should be properly wrapped and placed in a container to prevent loss or tampering.

NOTE: If you are still interested to see how “TOOLMARKS IDENTIFICATION” is applied in Firearms Identification CLICK HERE to get a PDF copy.



You can now take your final assessment regarding this last module.

If not ready, rewind and read again. If ready, GO AHEAD AND GOOD LUCK!

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Forensic Technology Center of Excellence - A program of the National Institute of Justice Logo

Two-Pronged Study of Bullets Fired by Consecutively Rifled Barrels – Forensic Technology Center of Excellence

Forensic Technology Center of Excellence

A program of the National Institute of Justice

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Two-pronged study of bullets fired by consecutively rifled barrels.

← Back to Firearm and Toolmarks Webinar Series

This webinar originally occurred on December 16, 2021 Duration: 1 hour

The 2016 President's Council of Advisors on Science and Technology (PCAST) Report brought forensics, and specifically firearms identification, into the spotlight once again. According to the PCAST Report, the field lacks empirical data supporting firearms examiners' ability to determine what source (i.e., firearm) created the markings left on fired bullets and cartridge cases.

In response to this criticism, Houston Forensic Science Center (HFSC) designed a black box study using ten consecutively rifled and three nonconsecutively rifled Ruger LCP barrels. Like many consecutively rifled barrel studies, test kits consisting of known samples (i.e., test fires) and unknown bullet samples were assembled and distributed to a broad group of firearms examiners across the Unites States and internationally. In this study, four different open-set test kits were created. Participants were asked to choose one of five possible conclusions for each comparison: identification, inconclusive A (leaning toward ID), inconclusive B (neutral), inconclusive C (leaning toward elimination), or elimination. The examiners' results were used to establish (an) error rate(s) for this study.

Unlike other consecutively rifled barrel studies, HFSC incorporated 3D technology to add a second prong to this study. HFSC teamed up with Dr. Alicia Carriquiry and Dr. Heike Hofmann of the Center for Statistics and Applications in Forensic Evidence (CSAFE). A sample of each of the four test kits was sent to Iowa State University, where the CSAFE team scanned each known and unknown bullet using a confocal light microscope. Based on these 3D scans, CSAFE researchers used a RandomForest score to establish similarity scores between the land engraved areas (LEAs) and predict source relationship between bullets. An error rate was established for this method of identifying a common source. CSAFE's similarity scores were compared to the examiners' results. The scoring of inconclusive results was of particular interest: there was no clear separation between inconclusive and elimination scores. However, there was a distinct separation of identification scores, as expected, highlighting the potential for the use of 3D technology in support of identifications in casework.

Detailed Learning Objectives

  • Attendees will learn the extent of subclass carry-over in consecutively rifled Ruger LCP barrels.
  • Attendees will understand the error rates associated when firearms examiners used traditional microscopy to identify which LCP barrel was used to fire unknown bullets.
  • Attendees will learn the the similarity scores generated when using 3D bullet scans and application of an algorithm to identify which LCP barrel was used to fire unknown bullets.
  • Dr. Heike Hofmann | Professor in Charge, Data Science Program, Iowa State University & Associate Director, Center for Statistics and Applications in Forensic Evidence
  • Melissa Nally | Senior Firearms Examiner, Houston Forensic Science Center

Funding for this Forensic Technology Center of Excellence webinar has been provided by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice.

The opinions, findings, and conclusions or  recommendations expressed in this webinar are those of  the presenter(s) and do not necessarily reflect those of the U.S. Department of Justice.

Contact us at  [email protected]  with any questions and subscribe to our  newsletter   for notifications.

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  9. Preventing Firearm Violence in Youth Through Evidence-Informed

    Firearm injuries are the leading cause of death for adolescents and young adults (AYA) aged 12-24 years in the U.S. The Society for Adolescent Health and Medicine (SAHM) believes that a comprehensive approach addressing firearm access for AYA can decrease the morbidity and mortality that AYA experience due to firearms. SAHM's position paper builds on the 2005 position statement, the ...

  10. Forensic Ballistics in Court: Interpretation and Presentation of

    Forensic Ballistics in Court: Interpretation and Presentation of Firearms Evidence is an accessible introduction to firearms and ballistics evidence and how this is analysed and presented as evidence in a court of law. The book approaches the subject in terms of the realities of case work, opening with a clear and illustrated explanation of the correct nomenclature for various weapon types and ...

  11. CSAFE Develops New Bullet Matching Technology

    Firearms examiners are charged with providing accurate assessments of bullet evidence, despite limitations in current analysis techniques. Current best practice relies on a subjective visual inspection of bullets and cartridge cases to determine if a particular gun was used at a crime scene.

  12. PDF Delivering Evidence-based and Culturally- Competent Firearm Suicide

    This presentation was prepared for the Mountain Plains Mental Health Technology Transfer Center ... We belong to the Technology Transfer Center (TTC) Network, a national network of training and technical ... •Little evidence that those who reside in firearm households have higher suicide risk than others.

  13. Firearms Examination: How It's Done

    Firearms Evidence that May be Found. The range of evidence in firearms-related cases can be as small as a piece of a bullet fragment which has rifling marks or as large as hundreds of bullets and cartridge cases and numerous firearms. Even from small samples, information can be developed to indicate the type of firearm used and possibly ...

  14. PDF A Simplified Guide To Firearms Examination

    Introduction. It's an all-‐too-‐common scenario: A person is found dead at a crime scene, the victim of a gunshot wound. Whether it's a cold-‐blooded robbery/homicide or a heated crime of passion, investigators must uncover the evidence and piece together the clues that will lead to the murder weapon.

  15. PDF Office of the Ohio Public Defender Pattern Evidence: A Primer

    Impression vs. Pattern Evidence ^Impression evidence is created when two objects come in contact with enough force to cause an impression. [Typically impression evidence is either two-dimensional— such as a fingerprint—or three-dimensional—such as the marks on a bullet caused by the barrel of a firearm." •National Institute of Justice

  16. Firearms 3D technology: Advantages and Value for Implementing 3D

    This presentation will demonstrate the effectiveness of integrating 3D technology into the forensic firearms/toolmarks discipline and the decision analysis used for selecting samples for virtual comparison. In 2009, a report by the National Academy of Sciences ("Strengthening Forensic Science in the United States: A Path Forward") called into question, amongst other issues, the objectivity ...

  17. Tech and Firearm Evidence Presentation.pptx

    View Tech and Firearm Evidence Presentation.pptx from SCIENCE 110 at Sussex Technical High School. Technology and Firearm Evidence Information By: Mary Messick How can new advances in technology

  18. 05.03 technology and firearm evidence presentation.pptx

    Advancements in Firearm Evidence Testing The Phenom SEM is a piece of equipment that gives forensic scientists the ability to search for gunshot residue particles. The Integrated Ballistics Identification System, or IBIS, is an automated ballistics imaging system that forensic scientists use in order to view a computerized source of images of bullets and casings from guns in a crime scene.

  19. Module 4

    (1) Evidence should be properly preserved for future identification and presentation during the trial of the case; (2) Firearm evidence must be kept in the proper place and under a proper condition so that it will be of greatest value in the prosecution of the case;

  20. Technology and Firearm Evidence Presentation.pptx

    Technology Advances: allows for investigators to easy digitize shell and bullet casing signatures Allows for quicker evidence matching Allows the review of large numbers of fired bullets. Ability to collects image data with the data acquisition station Ability to analyzes the image whose data has already been collected with the Image Analysis Station Ability to focus on the bullet's land ...

  21. Two-Pronged Study of Bullets Fired by Consecutively Rifled Barrels

    The 2016 President's Council of Advisors on Science and Technology (PCAST) Report brought forensics, and specifically firearms identification, into the spotlight once again. According to the PCAST Report, the field lacks empirical data supporting firearms examiners' ability to determine what source (i.e., firearm) created the markings left on ...

  22. unit 5 activity 2 .pdf

    Technology and Firearm Evidence Presentation 1y*) /V 0sZR 0° 6rRys`o_n. Prompt: Now that you are getting more familiar with many of the evidence types used to solve crimes, consider the following: How can new advances in technology help forensic scientists?

  23. PDF Firearm in forensic science: Comparative Study

    hence the accused person in the past have been convicted solely on the basis of firearm evidence. Therefore, when-ever a crime is occurred through firearm, the police or investigating officer from the crime scene submits it in the forensic laboratory for further investigation. ... BulletTrax-3-D image acquisition technology was specifically ...