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7.5×55mm Swiss full metal jacket, armor piercing, tracer, and spitzer projectiles. The three bullets on the right show cannelure evolution
Schlieren image sequence of a bullet traveling in free-flight, demonstrating the air pressure dynamics surrounding the bullet

A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. They are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax; and are made in various shapes and constructions (depending on the intended applications), including specialized functions such as hunting, target shooting, training, and combat. Bullets are often tapered, making them more aerodynamic. Bullet size is expressed by weight and diameter (referred to as "caliber") in both imperial and metric measurement systems.[1] Bullets do not normally contain explosives[2] but strike or damage the intended target by transferring kinetic energy upon impact and penetration.

Description

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The term bullet is from Early French, originating as the diminutive of the word boulle (boullet), which means "small ball".[3] Bullets are available singly (as in muzzle-loading and cap and ball firearms)[4] but are more often packaged with propellant as a cartridge ("round" of ammunition) consisting of the bullet (i.e., the projectile),[5] the case (which holds everything together), the propellant (which provides the majority of the energy to launch the projectile), and the primer (which ignites the propellant). Cartridges, in turn, may be held in a magazine, a clip, or a belt (for rapid-fire automatic firearms). Although the word bullet is often used in colloquial language to refer to a cartridge round, a bullet is not a cartridge but rather a component of one.[6] This use of the term bullet (when intending to describe a cartridge) often leads to confusion when a cartridge and all its components are specifically being referenced.

The sound of gunfire (i.e. the "muzzle report") is often accompanied with a loud bullwhip-like crack as the supersonic bullet pierces through the air, creating a sonic boom. Bullet speeds at various stages of flight depend on intrinsic factors such as sectional density, aerodynamic profile and ballistic coefficient, as well as extrinsic factors such as barometric pressure, humidity, air temperature and wind speed.[7][8] Subsonic cartridges fire bullets slower than the speed of sound, so there are no sonic booms. This means that a subsonic cartridge, such as .45 ACP, can be substantially quieter than a supersonic cartridge, such as the .223 Remington, even without the use of a suppressor.[9]

Bullets shot by firearms can be used for target practice or to injure or kill animals or people. Death can be by blood loss or damage to vital organs, or even asphyxiation if blood enters the lungs. Bullets are not the only projectiles shot from firearm-like equipment: BBs are shot from BB guns, airsoft pellets are shot by airsoft guns, paintballs are shot by paintball markers, and small rocks can be hurtled from slingshots. There are also flare guns, potato guns (and spud guns), tasers, bean bag rounds, grenade launchers, flash bangs, tear gas, RPGs, and missile launchers.

Speed

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Bullets used in many cartridges are fired at muzzle velocities faster than the speed of sound[10][11]—about 343 metres per second (1,130 ft/s) in dry air at 20 °C (68 °F)—and thus can travel substantial distances to their targets before any nearby observers hear the sound of the shots.

Rifle bullets, such as that of a Remington 223 firing lightweight varmint projectiles from a 24 inches (610 mm) barrel, leave the muzzle at speeds of up to 4,390 kilometres per hour (2,730 mph). A bullet from a 9 mm Luger handgun, reaches speeds of only 2,200 kilometres per hour (1,370 mph). Similarly, an AK-47, has a muzzle velocity of about 2,580 kilometres per hour (1,600 mph).[12]

History

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Round shot from the 16th century Mary Rose English warship, showing both stone and iron ball shot

The first true gun evolved in China from the fire lance (a bamboo tube that fired porcelain shrapnel) with the invention of the metal hand cannon sometime around 1288, which the Yuan dynasty used to win a decisive victory against Mongolian rebels. The artillery cannon appeared in 1326 and the European hand cannon in 1364. Early projectiles were made of stone. Eventually it was discovered that stone would not penetrate stone fortifications, which led to the use of denser materials as projectiles. Hand cannon projectiles developed in a similar manner. The first recorded instance of a metal ball from a hand cannon penetrating armor was in 1425.[13] Shot retrieved from the wreck of the Mary Rose (sunk in 1545, raised in 1982) are of different sizes, and some are stone while others are cast iron.[14]

The development of the hand culverin and matchlock arquebus brought about the use of cast lead balls as projectiles. The original round musket ball was smaller than the bore of the barrel. At first it was loaded into the barrel just resting upon the powder. Later, some sort of material was used as a wadding between the ball and the powder as well as over the ball to keep it in place,[15] it held the bullet firmly in the barrel and against the powder. (Bullets not firmly set on the powder risked exploding the barrel, with the condition known as a "short start".)[16]

The loading of muskets was therefore easy with the old smooth-bore Brown Bess and similar military muskets. The original muzzle-loading rifle, however, was loaded with a piece of leather or cloth wrapped around the ball, to allow the ball to engage the grooves in the barrel. Loading was a bit more difficult, particularly when the bore of the barrel was fouled from previous firings. For this reason, and because rifles were not often fitted for bayonets, early rifles were rarely used for military purposes, compared to muskets.

Matchlock musket balls, alleged to have been discovered on the battlefield of Naseby (1645)

There was a distinct change in the shape and function of the bullet during the first half of the 19th century, although experiments with various types of elongated projectiles had been made in Britain, America and France from the first half of the 18th century onwards.[17][18] In 1816, Capt. George Reichenbach of the Bavarian army invented a rifled-wall musket using cylindro-conical ammunition.[19] In 1826, Henri-Gustave Delvigne, a French infantry officer, invented a breech with abrupt shoulders on which a spherical bullet was rammed down until it caught the rifling grooves. Delvigne's method, however, deformed the bullet and was inaccurate. In 1855, a detachment of 1st U.S. Dragoons, while on patrol, traded lead for gold bullets with Pima Indians along the California–Arizona border.[20][21]

Square bullets have origins that almost pre-date civilization and were used in slings. They were typically made out of copper or lead. The most notable use of square bullet designs was by James Puckle and Kyle Tunis who patented them, where they were briefly used in one version of the Puckle gun. The early use of these in the black-powder era was soon discontinued because of the irregular and unpredictable flight patterns.

Pointed bullets

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Delvigne further developed cylindro-spherical (left) and cylindro-conical bullets (middle), which received the bullet grooves developed by Tamisier for stability

Delvigne continued to develop bullet design and by 1830 had started to develop cylindro-conical bullets. His bullet designs were improved by Francois Tamisier with the addition of "ball grooves" which are known as "cannelures", which moved the resistance of air behind the center of gravity of the bullet.[22] Tamisier also developed progressive rifling: the rifle grooves were deeper toward the breech, becoming shallower as they progressed toward the muzzle. This causes the bullet to be progressively molded into the grooves which increases range and accuracy.[23][24]

Before Tamisier's invention, the orientation of a cylindro-conical bullet tended to remain along its inertial axis, progressively setting it against its trajectory and increasingly meeting air resistance, which rendered the bullet's movement erratic.

Among the first pointed or "conical" bullets were those designed by Captain John Norton of the British Army in 1832. Norton's bullet had a hollow base made of lotus pith that on firing expanded under pressure to engage with a barrel's rifling.[25] The British Board of Ordnance rejected it because spherical bullets had been in use for the previous 300 years.[26] Renowned English gunsmith William Greener invented the Greener bullet in 1836. Greener fitted the hollow base of an oval bullet with a wooden plug that more reliably forced the base of the bullet to expand and catch the rifling. Tests proved that Greener's bullet was effective, but the military rejected it because, being two parts, they judged it as too complicated to produce.[27]

Minié ball ammunition

The carabine à tige, developed by Louis-Étienne de Thouvenin in 1844, was an improvement of Delvigne's design. The rifle barrel has a forcing plug in the breech of the barrel to mold the bullet into the rifling with the use of a special ramrod. While successful in increasing accuracy, it was difficult to clean.

1855 Minié ball design from the U.S. Arsenal, Harper's Ferry, West Virginia

The soft lead Minié ball was first introduced in 1847 by Claude-Étienne Minié, a captain in the French Army. It was another improvement of the work done by Delvigne. The bullet was conical in shape with a hollow cavity in the rear, which was fitted with a small iron cap instead of a wooden plug. When fired, the iron cap forced itself into the hollow cavity at the rear of the bullet, thus expanding the sides of the bullet to grip and engage the rifling. In 1851, the British adopted the Minié ball for their 702-inch Pattern 1851 Minié rifle. In 1855, James Burton, a machinist at the U.S. Armory at Harper's Ferry, West Virginia, improved the Minié ball further by eliminating the metal cup in the bottom of the bullet.[28][29] The Minié ball first saw widespread use in the Crimean War (1853–1856). Roughly 90% of the battlefield casualties in the American Civil War (1861–1865) were caused by Minié balls fired from rifled muskets.[30] A similar bullet called the Nessler ball was also developed for smoothbore muskets.[31]

Between 1854 and 1857, Sir Joseph Whitworth conducted a long series of rifle experiments and proved, among other points, the advantages of a smaller bore and, in particular, of an elongated bullet. The Whitworth bullet was made to fit the grooves of the rifle mechanically. The Whitworth rifle was never adopted by the government, although it was used extensively for match purposes and target practice between 1857 and 1866. In 1861, W. B. Chace approached President Abraham Lincoln with an improved ball design for muskets. In firing over the Potomac River, where the Chace ball and the round ball were alternated, Lincoln observed that the Chace design carried a third or more farther fired at the same elevation. Although Lincoln recommended testing, it never took place.[32]

Around 1862, W. E. Metford carried out an exhaustive series of experiments on bullets and rifling, and he invented the important system of light rifling with increasing spiral and a hardened bullet. The combined result was that, in December 1888, the Lee–Metford small-bore (.303", 7.70 mm) rifle, Mark I, was adopted for the British army. The Lee–Metford was the predecessor of the Lee–Enfield.[33]

Modern bullets

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.270 Winchester ammunition:
  1. 100-grain (6.5 g) – hollow point
  2. 115-grain (7.5 g) – FMJBT
  3. 130-grain (8.4 g) – soft point
  4. 150-grain (9.7 g) – round nose

The next important change in the history of the rifle bullet occurred in 1882, when Lieutenant Colonel Eduard Rubin, director of the Swiss Army Laboratory at Thun, invented the copper-jacketed bullet — an elongated bullet with a lead core in a copper jacket. It was also small bore (7.5 and 8 mm) and it is the precursor of the 8 mm Lebel bullet adopted for the smokeless powder ammunition of the Lebel Model 1886 rifle. The surface of lead bullets fired at high velocity may melt from the hot gases behind and friction within the bore. Because copper has a higher melting point, and greater specific heat capacity, and higher hardness, copper-jacketed bullets allow greater muzzle velocities.

.303 inch (7.7 mm) centrefire, FMJ rimmed ammunition

European advances in aerodynamics led to the pointed spitzer bullet. By the beginning of the 20th century, most world armies had begun the transition to spitzer bullets. These bullets flew for greater distances more accurately and transferred more kinetic energy. Spitzer bullets combined with machine guns greatly increased lethality on the battlefield.

Spitzer bullets were streamlined at the base with the boat tail. In the trajectory of a bullet, as air passes over a bullet at high speed, a vacuum is created at the end of the bullet, slowing the projectile. The streamlined boat tail design reduces this form drag by allowing the air to flow along the surface of the tapering end. The resulting aerodynamic advantage is currently seen as the optimum shape for rifle technology. The first combination spitzer and boat-tail bullet, named balle D by its inventor Captain Georges Desaleux, was introduced as standard military ammunition in 1901, for the French Lebel Model 1886 rifle.

A ballistic tip bullet is a hollow-point rifle bullet that has a plastic tip on the end of the bullet. This improves external ballistics by streamlining the bullet, allowing it to cut through the air more easily, and improves terminal ballistics by allowing the bullet to act as a jacketed hollow point. As a side effect, it also feeds better in weapons that have trouble feeding rounds that are not full metal jacket rounds.

Design

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A bullet in mid flight

Bullet designs have to solve two primary problems. In the barrel, they must first form a seal with the gun's bore. If a strong seal is not achieved, gas from the propellant charge leaks past the bullet, thus reducing efficiency and possibly accuracy. The bullet must also engage the rifling without damaging or excessively fouling the gun's bore and without distorting the bullet, which will also reduce accuracy. Bullets must have a surface that forms this seal without excessive friction. These interactions between bullet and bore are termed internal ballistics. Bullets must be produced to a high standard, as surface imperfections can affect firing accuracy.

The physics affecting the bullet once it leaves the barrel is termed external ballistics. The primary factors affecting the aerodynamics of a bullet in flight are the bullet's shape and the rotation imparted by the rifling of the gun barrel.[34] Rotational forces stabilize the bullet gyroscopically as well as aerodynamically. Any asymmetry in the bullet is largely canceled as it spins. However, a spin rate greater than the optimum value adds more trouble than good, by magnifying the smaller asymmetries or sometimes resulting in the bullet breaking apart in flight. With smooth-bore firearms, a spherical shape is optimal because no matter how the bullet is oriented, its aerodynamics are similar. These unstable bullets tumble erratically and provide only moderate accuracy; however, the aerodynamic shape changed little for centuries. Generally, bullet shapes are a compromise between aerodynamics, interior ballistic necessities, and terminal ballistics requirements.

Terminal ballistics and stopping power are aspects of bullet design that affect what happens when a bullet impacts with an object. The outcome of the impact is determined by the composition and density of the target material, the angle of incidence, and the velocity and physical characteristics of the bullet. Bullets are generally designed to penetrate, deform, or break apart. For a given material and bullet, the strike velocity is the primary factor that determines which outcome is achieved.

Bullet shapes are many and varied. With a mold, bullets can be made at home for reloading ammunition, where local laws allow. Hand-casting, however, is only time- and cost-effective for solid lead bullets. Cast and jacketed bullets are also commercially available from numerous manufacturers for handloading and are most often more convenient than casting bullets from bulk or scrap lead.

In recent years, manufacturers have introduced bullet designs that rely on computer numerical control (CNC) machining to achieve precise, repeatable geometries not possible with traditional swaging or casting. These designs often feature patented profiles with radial flutes, pressure cavities, or meplat modifications intended to manipulate fluid displacement, induce controlled expansion, or promote bullet tumbling upon impact.

One notable example includes the designs patented by Lehigh Defense, which incorporate machined flutes that channel hydraulic force to create large wound cavities and ensure consistent terminal performance. These bullets are often monolithic in composition and used in hunting and self-defense contexts where expansion and barrier penetration are critical.[35][36][37]

Propulsion

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Propulsion of the ball can happen via several methods:

Materials

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Expanding bullet loaded in a 6.5×55mm before and after expanding. The long base and small expanded diameter show that this is a bullet designed for deep penetration on large game. The bullet in the photo traveled more than halfway through a moose before coming to rest, performing as designed.

Bullets for black powder, or muzzle-loading firearms, were classically molded from pure lead. This worked well for low-speed bullets, fired at velocities of less than 450 m/s (1,475 ft/s). For slightly higher-speed bullets fired in modern firearms, a harder alloy of lead and tin or typesetter's lead (used to mold linotype) works very well. For even higher-speed bullet use, jacketed lead bullets are used. The common element in all of these, lead, is widely used because it is very dense, thereby providing a high amount of mass—and thus, kinetic energy—for a given volume. Lead is also cheap, easy to obtain, easy to work, and melts at a low temperature, which results in comparatively easy fabrication of bullets.

  • Lead: simple cast, extruded, swaged, or otherwise fabricated lead slugs are the simplest form of bullets. At speeds of greater than 300 m/s (1,000 ft/s) (common in most handguns), lead is deposited in rifled bores at an ever-increasing rate. Alloying the lead with a small percentage of tin and/or antimony serves to reduce this effect but grows less effective as velocities are increased. A cup made of harder metal, such as copper, placed at the base of the bullet and called a gas check, is often used to decrease lead deposits by protecting the rear of the bullet against melting when fired at higher pressures, but this does not solve the problem at higher velocities. A modern solution is to powder coat the lead projectile, encasing it in a protective skin, allowing higher velocities to be achieved without lead deposits.
  • Jacketed lead: bullets intended for even higher-velocity applications generally have a lead core that is jacketed or plated with gilding metal, cupronickel, copper alloys, or steel; a thin layer of harder metal protects the softer lead core when the bullet is passing through the barrel and during flight, which allows delivering the bullet intact to the target. There, the heavy lead core delivers its kinetic energy to the target. Full metal jacket or "ball" bullets (cartridges with ball bullets, which despite the name are not spherical, are called ball ammunition) are completely encased in the harder metal jacket, except for the base. Some bullet jackets do not extend to the front of the bullet, to aid expansion and increase lethality; these are called soft point (if the exposed lead tip is solid) or hollow point bullets (if a cavity or hole is present). Steel bullets are often plated with copper or other metals for corrosion resistance during long periods of storage. Synthetic jacket materials such as nylon and Teflon have been used, with limited success, especially in rifles; however, hollow point bullets with plastic aerodynamic tips have been very successful at both improving accuracy and enhancing expansion. Newer plastic coatings for handgun bullets, such as Teflon-coated bullets, are making their way into the market.
Hard cast solid bullet (left), with gas check (center) and lubrication (right)
A modern centerfire cartridge consisting of the following: 1. bullet, as the projectile; 2. metallic case, which holds all parts together; 3. propellant, for example gunpowder or cordite;4. rim, which provides the extractor on the firearm a place to grip the case to remove it from the chamber once fired; 5. primer, which ignites the propellant.
  • Solid or monolithic solid: mono-metal bullets intended for deep penetration in big game animals and slender shaped very-low-drag projectiles for long range shooting are produced out of metals like oxygen-free copper and alloys like cupronickel, tellurium copper and brass (e.g., highly machinable UNS C36000 free-cutting brass). Often these projectiles are turned on precision CNC lathes. In the case of solids, and the ruggedness of the game animals on which they are used, e.g., the African buffalo or elephant, expansion is almost entirely relinquished for the necessary penetration. In shotgunning, "slug" loads are often solid large single lead projectiles, sometimes with a hollow point, used for deer or wild pig hunting in jurisdictions that do not allow hunting with rifles (because a missed slug shot will travel considerably less far than a rifle bullet).
    • Fluted: in appearance, these are solid bullets with scalloped sides (missing material). The theory is that the flutes produce hydraulic jetting when passing through tissue, creating a wound channel larger than that made by conventional expanding ammunition such as hollow point bullets.
    • Hard cast: a hard lead alloy intended to reduce fouling of rifling grooves (especially of the polygonal rifling used in some popular pistols). Benefits include simpler manufacture than jacketed bullets and good performance against hard targets; limitations are an inability to mushroom and subsequent over-penetration of soft targets.
  • Blank: wax, paper, plastic, and other materials are used to simulate live gunfire and are intended only to hold the powder in a blank cartridge and to produce noise, flame and smoke. The "bullet" may be captured in a purpose-designed device or it may be allowed to expend what little energy it has in the air. Some blank cartridges are crimped or closed at the end and do not contain any bullet; some are fully loaded cartridges (without bullets) designed to propel rifle grenades. The force of the expanding gas from blank cartridges can be lethal at short range; fatal accidents have occurred with blank cartridges (e.g., the death of actor Jon-Erik Hexum).
  • Practice: made from lightweight materials like rubber, wax, wood, plastic, or lightweight metal, practice bullets are intended for short-range target work only. Because of their weight and low velocity, they have limited range.
  • Polymer: these are metal-polymer composites, generally lighter and having higher velocities than pure metal bullets of the same dimensions. They permit unusual designs that are difficult with conventional casting or lathing.
  • Less lethal, or less than lethal: Rubber bullets, plastic bullets, and beanbags are designed to be non-lethal, e.g., for use in riot control. They are generally low velocity and are fired from shotguns, grenade launchers, paint ball guns, or specially designed firearms and air gun devices.
  • Incendiary: these bullets are made with explosive or flammable mixtures in the tips that are designed to ignite on contact with a target. The intent is to ignite fuel or munitions in the target area, thereby adding to the destructive power of the bullet.
  • Exploding: similar to the incendiary bullet, this type of projectile is designed to explode upon hitting a hard surface, preferably the bone of the intended target. Not to be mistaken for cannon shells or grenades with fuse devices, these bullets have only cavities filled with a small amount of high explosive depending on the velocity and deformation upon impact to detonate. Exploding bullets have been used in various heavy machine guns and in anti-materiel rifles.
  • Tracer: these have hollow backs, filled with a flare material. Usually this is a mixture of magnesium, a perchlorate, and strontium salts to yield a bright red color, although other materials providing other colors have also sometimes been used. Tracer material burns out after a certain amount of time. This allows the shooter to visually trace the flight path of the projectile and thus make necessary ballistic corrections, without having to confirm projectile impacts and without even using the sights of the weapon. This type of round is also used by all branches of the United States military in combat environments as a signaling device to friendly forces. Normally it is loaded at a four to one ratio with ball ammunition.
  • Armor-piercing: jacketed designs where the core material is a very hard, high-density metal such as tungsten, tungsten carbide, depleted uranium, or steel. A pointed tip is often used, but a flat tip on the penetrator portion is generally more effective.[38]
  • Nontoxic shot: steel, bismuth, tungsten, and other alloys prevent release of toxic lead into the environment. Regulations in several countries mandate the use of nontoxic projectiles especially when waterfowl hunting. It has been found that birds swallow small lead shot for their gizzards to grind food (as they would swallow pebbles of similar size), and the effects of lead poisoning by grinding of lead pellets against food means lead poisoning effects are magnified. Such concerns apply primarily to shotguns firing pellets (shot) and not bullets, but there is evidence suggesting that consumption of spent rifle and pistol ammunition is also hazardous to wildlife.[39] Reduction of hazardous substances legislation has also been applied to bullets on occasion to reduce the impact of lead on the environment at shooting ranges.
  • Blended-metal: bullets made using cores from powdered metals other than lead with binder or sometimes sintered.
  • Frangible: designed to disintegrate into tiny particles upon impact to minimize their penetration for reasons of range safety, to limit environmental impact, or to limit the shoot-through danger behind the intended target. An example is the Glaser Safety Slug, usually a pistol caliber bullet made from an amalgam of lead shot and a hard (and thus frangible) plastic binder designed to penetrate a human target and release its component shot pellets without exiting the target.
  • Multiple projectile: bullets that are made of separate slugs that fit together inside the cartridge and act as a single projectile inside the barrel as they are fired. The projectiles part in flight but are held in formation by tethers that keep the individual parts of the "bullet" from flying too far away from each other. The intention of such ammo is to increase hit chance by giving a shot-like spread to rifled slug firing guns, while maintaining a consistency in shot groupings. Multiple impact bullets may be less stable in flight than conventional solid bullets because of the added drag from the tether line holding the pieces in formation, and each projectile affects the flight of all the others. This may limit the benefit provided by the spread of each bullet at longer ranges.
  • Expanding bullets are designed to increase in diameter upon impact with a target, maximizing the transfer of energy and creating a larger wound channel.[40] These bullets are often made with a lead core and a copper jacket, though variations like MRX bullets have tungsten in its core.[41] The polymer tip in expanding bullets is designed to enhance aerodynamics for shooting at flat long-range trajectories.[42]

Treaties and prohibitions

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Poisonous bullets were a subject to an international agreement as early as the Strasbourg Agreement (1675). The Saint Petersburg Declaration of 1868 prohibited the use of explosive projectiles weighing less than 400 grams.[43] The Hague Conventions prohibits certain kinds of ammunition for use in war. These include poisoned[44][45] and expanding[46][47] bullets. Protocol III of the 1983 Convention on Certain Conventional Weapons, an annexed protocol to the Geneva Conventions, prohibits the use of incendiary ammunitions against civilians.[48]

Types of bullets

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Some types of bullets include:

See also

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  • Flechette – Pointed, fin-stabilized steel projectile
  • Meplat – Flat or open tip on nose of a bullet
  • Smart bullet – Guided bullet

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Bullet

View on Grokipedia
from Grokipedia

A bullet is a single, typically metallic projectile designed to be expelled from the barrel of a firearm by the explosive expansion of propellant gases, serving as the primary component that delivers kinetic energy to a target. Bullets differ from spherical shot used in shotguns, being optimized for rifled barrels to impart spin for stability and accuracy. Historically, early bullets took the form of simple lead balls loaded into muskets from the onward, limited in range and precision until the 19th-century development of elongated cylindro-conical designs like the , which expanded upon firing to engage while enabling faster muzzle-loading rifles. This innovation facilitated greater effective range and lethality in conflicts such as the , marking a shift toward modern grounded in empirical improvements in and material composition. The subsequent integration of bullets into self-contained metallic cartridges in the mid-19th century revolutionized repeating firearms, enhancing reliability and fire rates through standardized manufacturing. Contemporary bullets exhibit diverse constructions to suit specific ballistic requirements, including types for reliable feeding and penetration in military applications, hollow-point variants that promote rapid expansion and tissue disruption for or , and frangible options that disintegrate on impact to minimize over-penetration risks. Materials commonly include lead cores sheathed in or other alloys to balance weight, retention, and barrel wear, with designs influenced by principles emphasizing energy transfer over mere penetration. These variations underscore bullets' role as engineered components prioritizing causal efficacy in imparting , as dictated by , , and target interaction dynamics.

Fundamentals

Definition and Components

A bullet is the solid projectile component of a cartridge, distinct from the casing, primer, and , and designed to be expelled from the barrel by the pressure of expanding gases generated by ignited . Typically cylindrical or ogive-shaped for aerodynamic stability, it travels at velocities ranging from subsonic to over 1,200 meters per second depending on and load, with varying from under 1 gram in small- rounds to over 30 grams in large rifle bullets. The term "bullet" derives from historical lead balls but now encompasses modern precision-engineered s optimized for engagement via . Core construction forms the bullet's foundational mass, usually lead or lead-antimony alloys (e.g., 6% antimony for hardness) due to their density (11.34 g/cm³ for pure lead) enabling kinetic energy delivery while allowing deformation on impact. Jacketing, common in high-velocity designs since the late 19th century, encases the core in a harder metal sheath—typically gilding metal (90% copper, 10% zinc), pure copper, or occasionally steel—to withstand barrel pressures exceeding 50,000 psi without fragmenting or fouling the bore with lead vapor. The bullet's forward section includes the (curved nose profile) and (flat or pointed tip), which influence drag coefficients (e.g., 0.1-0.3 for boat-tail designs) and initial yaw stability. The rear base, often flat or tapered (boattail for reduced base drag), seals against propellant gases; features like cannelures (grooves) secure it in the cartridge case via crimping. Unjacketed or frangible variants use sintered powder or polymer composites for specialized applications, such as reduced in training.

Basic Principles of Operation

The basic operation of a bullet in a firearm cartridge commences with the ignition of the propellant charge. Upon the firing pin striking the primer, a chemical reaction generates heat that ignites the smokeless powder or black powder, which deflagrates rapidly to produce expanding gases. These gases create chamber pressure exceeding 50,000 psi in high-powered rifle cartridges, forcefully propelling the bullet from its crimp in the cartridge case down the barrel. As the bullet accelerates along the bore, its driving bands or body engages the barrel's —helical grooves typically twisted at rates from 1:7 to 1:20 inches per turn, depending on and intended . This interaction imparts to the bullet, causing it to rotate at rates up to 300,000 RPM in projectiles, which induces gyroscopic for aerodynamic stability and resistance to yawing or tumbling. The bullet's material, often a lead core jacketed in copper or , deforms slightly under pressure to achieve , sealing the bore against gas escape and maximizing efficiency. Upon reaching the muzzle, the bullet exits at velocities ranging from 800 fps in rounds to over 3,000 fps in , with derived primarily from the 's conversion. This process adheres to conservation of , wherein the impulse equals the bullet's forward plus propellant gas ejection.

Physics and Ballistics

Internal and External Ballistics

Internal ballistics examines the motion and forces acting on a bullet from propellant ignition until it exits the firearm's muzzle. The process begins when the primer strikes ignite the smokeless powder, causing rapid deflagration that generates expanding gases and peak chamber pressures typically ranging from 30,000 to 65,000 psi in modern small arms cartridges, depending on caliber and load. These pressures act on the bullet base over the bore area, producing forward force via Newton's second law, F = P × A, where P is pressure and A is cross-sectional area, accelerating the projectile down the barrel. Bullet is nonlinear, with initial rapid rise followed by expansion of the gas behind the moving , leading to decreasing as the bullet travels. For a 9 mm bullet in a 4.9-inch barrel achieving 350 m/s , average approximates 3.5 × 10^5 m/s², derived from v² = 2as assuming constant for simplification, though actual profiles require piezo-electric measurements for precision. Barrel length positively correlates with up to optimal powder burn completion, as longer bores allow more sustained ; for example, extending barrels from 16 to 24 inches can increase velocity by 20-30% in high-velocity rounds. grooves, cut at twist rates like 1:10 inches (one rotation per 10 inches of travel), engage the bullet's driving bands or jacket, imparting spin for later stability while introducing frictional drag that slightly reduces velocity, typically by 1-5% compared to smoothbores. characteristics, including grain geometry and , critically influence curves; progressive-burning powders maintain higher average pressures in longer barrels, optimizing energy transfer. External ballistics analyzes the projectile's free-flight path from muzzle to impact, dominated by initial , gravitational acceleration (9.81 m/s² downward), and aerodynamic drag. Absent drag, the trajectory follows a parabolic arc with vertical drop h = (1/2)gt², but air resistance imposes drag D = (1/2)ρv²C_dA, where ρ is air , v , C_d (0.2-0.5 for typical bullets), and A frontal area, decelerating the bullet and flattening early before steeper descent at lower speeds. The ballistic coefficient (BC), defined as BC = m / (C_d × d²) with m and d , quantifies drag resistance; higher BC values (e.g., 0.5+ for boat-tail designs) extend effective range by minimizing loss, as seen in bullets retaining supersonic speeds beyond 800 meters under standard conditions. Rifling-induced spin, reaching 150,000-300,000 rpm for common rifle twists, provides gyroscopic precession stability against yaw and tumbling, though it introduces the Magnus effect—lateral force from spin interacting with crosswinds or density gradients, causing drift up to several feet at 1,000 yards. Environmental variables like wind (lateral drift proportional to v^{-1} roughly), temperature (affecting ρ and powder burn), and altitude further perturb the path; for instance, a 10 mph crosswind deflects a .223 Remington bullet ~10 inches at 300 yards. Trajectory computations often employ numerical integration of differential equations or lookup tables from ballistics software calibrated against Doppler radar data for accuracy.

Terminal Ballistics and Wound Dynamics

examines the behavior of a bullet upon striking a target, including , deformation or fragmentation, and the resultant energy transfer to tissues. In or targets, this process governs formation, with empirical testing typically conducted using 10% ordnance calibrated to simulate density and elasticity. Key determinants include bullet , mass, construction (e.g., versus expanding hollow-point), and impact angle, as higher —calculated as 12mv2\frac{1}{2}mv^2, where mm is mass and vv is —facilitates greater tissue disruption but risks over-penetration if unchecked. Wound dynamics primarily involve two cavities: the permanent cavity, formed by direct crushing and displacement of tissue by the bullet's path, which correlates directly with penetration length and frontal area; and the temporary cavity, a radial expansion of tissues due to inertial stretching from kinetic energy deposition. For handgun bullets (typically 300–500 m/s muzzle velocity), temporary cavities measure less than 10 cm in diameter and dissipate within milliseconds, causing negligible remote damage in elastic structures like muscle or organs, as pressures fall below 1 MPa—insufficient to lacerate intact vessels or nerves beyond the permanent track. Rifle bullets exceeding 600 m/s, however, generate temporary cavities up to 30 cm or more, potentially amplifying injury through shear forces, though incapacitation still hinges on vital structure disruption rather than cavity size alone. Bullet yaw or tumbling post-impact, often induced by tissue resistance, increases effective diameter and tissue laceration, as observed in gelatin tests where yaw onset within 10–15 cm of entry doubles energy transfer efficiency. Fragmentation occurs when bullets exceed material yield strength upon deceleration, scattering or core pieces to create multiple wound channels; this is pronounced in soft-point or polymer-tipped designs at velocities over 700 m/s, with fragments penetrating 5–20 cm radially. Conversely, bullets resist deformation, prioritizing deep straight-line penetration (often >30 cm) over expansion, which military studies from the 1980s deemed optimal for barrier defeat but suboptimal for rapid incapacitation in unarmored threats due to narrower permanent cavities (typically 0.3–0.5 cm diameter). The FBI's wounding criteria, derived from 1989 agent-involved shooting analyses, prioritize 30–50 cm penetration in to traverse , followed by frontal area expansion (ideally 1.5–2x ) and minimal over-penetration risk, as shallow wounds (<30 cm) fail to reliably reach cardiovascular structures through layered clothing or bone. Hydrostatic shock—the hypothesis of remote neural or organ damage via propagating pressure waves—lacks empirical substantiation for handgun or most rifle calibers in ballistic gelatin or autopsy data, with peak pressures (200–500 kPa) confined to <5 cm from the track and decaying exponentially without causing sub-lethal CNS disruption. Proponents cite high-velocity impacts (>900 m/s) in large game, where spinal shock analogs appear in ~10% of cases, but controlled human surrogate tests show no faster incapacitation than hemorrhage or structural hits; Martin Fackler's 1980s research at Letterman Army Institute, analyzing over 1,000 swine wounds, concluded shock effects are artifacts of direct trauma, not hydraulic transmission, emphasizing instead the causal primacy of blood loss (requiring 30% volume depletion for hypotension) or CNS severance for physiological stoppage within 10–15 seconds. Shot placement thus overrides bullet design, with torso hits incapacitating via ~1–2 liter/minute hemorrhage only if arteries or heart are severed, per forensic reviews of 1980–1990 U.S. law enforcement data showing 60–70% one-shot stops from CNS impacts versus <30% from extremities.

Speed, Trajectory, and Environmental Factors

, the speed of a bullet as it exits the barrel, typically ranges from 300 meters per second (1,000 feet per second) for to over 1,200 meters per second (4,000 feet per second) for high-velocity rounds. Factors such as charge, barrel length, and bullet weight directly influence this initial speed, with longer barrels generally imparting higher velocities due to prolonged . Once in flight, a bullet's follows a parabolic arc primarily governed by , which causes vertical drop independent of horizontal velocity in the absence of air resistance. The drop distance can be approximated by d=12gt2d = \frac{1}{2} g t^2, where gg is (approximately 9.8 m/s²) and tt is , calculated as range divided by horizontal velocity component. For example, a bullet traveling 300 meters at 800 m/s experiences about 1.5 meters of drop due to alone, though actual paths deviate due to drag. Air resistance, quantified by the bullet's (BC)—a measure of its ability to overcome drag—significantly alters , with higher BC values (e.g., above 0.5 for streamlined bullets) resulting in flatter paths and less velocity loss. Drag force depends on air density, bullet shape, and speed, slowing the and steepening the curve beyond simple parabolic motion. Environmental factors further modify : wind induces lateral drift proportional to speed and , potentially shifting impact by meters at long ranges; higher altitudes reduce air , decreasing for extended flat trajectories; elevated temperatures lower air similarly while also increasing burn rates, boosting by up to 1-2% per 10°C rise but risking pressure inconsistencies. has minimal direct effect but correlates with changes. Shooters compensate using ballistic calculators incorporating these variables for precise aiming adjustments.

Historical Development

Ancient and Early Modern Projectiles

The earliest documented use of lead projectiles in firearms dates to the mid-14th century in , where hand cannons employed irregularly shaped "clod shot" cast from lead as . These primitive projectiles, evidenced in records from 1375, offered improved and moldability over stone or iron alternatives but lacked uniformity. Hand cannons, emerging around 1350, typically fired such lead pieces or stone balls through wrought-iron barrels, achieving ranges of approximately 50-100 meters with low accuracy due to smooth bores and loose fits. By the , the transition to spherical cast lead balls marked a key advancement in design for evolving handgonnes and early arquebuses, standardizing for mechanisms introduced around 1400. Lead's high density—11.34 g/cm³—provided superior compared to stone, while its low of 327°C enabled simple in two-part molds over open fires. These balls, often slightly undersized for the barrel to allow powder residue clearance, weighed 20-50 grams depending on , with bores ranging from 15-20 mm. In the early (circa 1500-1800), round lead balls dominated projectiles for , which superseded arquebuses as weapons by the early . Standard musket balls measured 0.69 inches (17.5 mm) in diameter for common calibers like the British Long Land Pattern, weighing about 1 (28 grams) to deliver sufficient to penetrate armor at 100 yards. Production involved pouring molten lead alloys—sometimes with trace tin for hardness—into bullet molds, yielding balls swaged or hammered for sphericity; variations included buckshot combinations for close-range antipersonnel effects. Despite occasional use of iron or stone for economy in , lead prevailed for handheld firearms due to its ability to expand on impact, enhancing wounding potential without .

19th-Century Innovations

The marked a pivotal shift in bullet design from spherical lead balls to elongated, cylindrical projectiles optimized for rifled barrels, significantly enhancing range and accuracy in firearms. Prior to this era, smoothbore muskets relied on round balls that limited effective firing distances to approximately 100 yards due to poor and lack of . Innovations in the early 1800s, such as Henri-Gustave Delvigne's design featuring a cylindrical bullet with an annular base intended to expand upon impact with the , laid groundwork for overcoming loading difficulties in rifled arms. The most transformative advancement was the , patented by Captain Claude-Étienne Minié in 1849, which addressed the challenges of muzzle-loading rifled muskets by incorporating a hollow base and conical cavity. Crafted from soft lead alloy, the Minié bullet's skirt expanded via propellant gases upon ignition, sealing the bore and engaging the grooves for gyroscopic stabilization without requiring a tight initial fit, thus enabling rapid loading comparable to smoothbores. This design increased muzzle velocities to around 900-1,000 feet per second and extended effective ranges to 300-500 yards, as demonstrated in the (1853-1856) where British forces adopted the rifle-musket chambered for it. Variants like the Burton-Minié bullet, developed by U.S. Army Captain James H. Burton in 1855 and tested at , featured multiple grease grooves and a smaller cavity for improved expansion and reduced lead fouling, becoming standard in the (1861-1865). The Minié's higher impact energy and tendency to deform or fragment upon hitting tissue resulted in severe, often mutilating wounds, contributing to unprecedented battlefield casualties; Union Army records indicate over 95% of extracted projectiles were Minié balls. By the mid-19th century, these innovations facilitated the transition to breech-loading rifles and early metallic cartridges, such as the 1860 rimfire round, which encased elongated lead bullets in for reliability and weather resistance. Late-century developments included ogival (pointed) nose designs by inventors like William Greener, further refining for velocities exceeding 1,200 feet per second in rifles, setting the stage for modern . These changes, driven by demands for precision and lethality, fundamentally altered and warfare dynamics.

20th-Century Advancements

![.303 British ammunition][float-right] The early marked a shift toward aerodynamic refinements in bullet design, primarily through the adoption of spitzer (pointed) bullets, which reduced air resistance compared to earlier round-nosed projectiles, enabling flatter trajectories and greater effective ranges. pioneered this with the "Balle D" spitzer for the 8mm Lebel in 1898, firing a 198-grain bullet at 2,300 fps that remained supersonic beyond 500 yards. followed in 1905 by modifying its 7.92x57mm Patrone '88 cartridge to incorporate a spitzer projectile known as Spitzgeschoß, enhancing performance in rifles. By , most major armies had transitioned to spitzer designs, which contributed to improved rifle effectiveness at distances up to 800 meters. Further ballistic optimization came with the boat-tail base, introduced in 1901, which tapered the rear of the bullet to minimize base drag and improve long-range stability without significantly increasing manufacturing complexity. This feature, often combined with spitzer noses, became common in military and sporting ammunition by the interwar period, as seen in the .270 Winchester cartridge introduced in 1925, which utilized boat-tailed spitzers for varmint and big-game hunting. Military requirements drove the standardization of (FMJ) bullets, where a lead core is fully encased in a harder metal like or , ensuring reliable feeding in automatic weapons and compliance with the 1899 Hague Declaration's ban on expanding ammunition in international warfare. FMJ designs predominated in both world wars, with rifle bullets often featuring cores for armor-piercing variants, such as the German 7.92mm s.S. Patrone used extensively from 1933 onward. Specialized projectiles emerged to address tactical needs, including tracer rounds for gunnery observation and incendiary types for anti-aircraft and anti-materiel roles. The developed the first practical tracer in 1915 for the cartridge, using a that produced a visible white trace for 400-500 yards to aid in adjusting fire during . The U.S. followed with the .30 M1 tracer in 1925, refined through for better burn consistency and reduced visibility to the enemy. Civilian and applications saw advancements in expanding bullets, building on late-19th-century soft-point designs. Jacketed hollow-point (JHP) bullets gained prominence in the mid-20th century, particularly for handguns, with casting techniques enabling controlled expansion upon impact to maximize while minimizing over-penetration; these were widely used by the in calibers like and 9mm. Hollow points, often with copper or jackets, improved terminal performance for and by creating larger wound channels through mushrooming, though their adoption in contexts remained limited due to international prohibitions.

Recent Developments (Post-2000)

Post-2000 developments in bullet technology have emphasized enhanced precision, material innovations, and environmental adaptations, driven by military research and regulatory pressures. , advanced , and polymer composites have enabled projectiles with superior and reduced weight, improving and terminal in small arms. For instance, radar-based testing since the mid-2010s has refined bullet shapes for flatter trajectories and better energy retention, allowing traditional calibers like 9mm to achieve ballistic efficiencies previously associated with larger rounds. A significant military advancement is the integration of guidance systems into small-caliber bullets, exemplified by the U.S. program. Initiated in the early , developed self-steering .50-caliber projectiles capable of real-time optical tracking and course correction via onboard fins, demonstrated in live-fire tests in 2014 and 2015 to hit evading targets at sniper ranges exceeding 2 kilometers. This technology aims to counter wind drift and shooter error, potentially increasing hit probabilities from under 50% to near 100% under adverse conditions, though deployment remains limited due to cost and complexity. Environmental concerns have spurred lead-free bullet innovations, using copper alloys or composites to minimize poisoning and human exposure. mandated lead-free in 2019, prompting designs like copper hollow-points that expand reliably while retaining over 90% weight at ranges up to 260 yards, as tested in ballistic media. implemented a nationwide ban on lead for starting in 2024, accelerating commercial adoption of non-toxic alternatives that match lead's penetration but with adjusted geometries for consistent fragmentation. These projectiles, while effective for ethical , often require adjustments due to differing and barrel characteristics compared to lead cores. Emerging "smart" features include self-destructing mechanisms in training rounds to reduce range contamination and sensor-equipped prototypes for reduced , though widespread fielding awaits . Overall, these post-2000 shifts prioritize , , and integration with digital fire control systems, reflecting causal trade-offs between performance gains and manufacturing costs.

Design and Manufacturing

Projectile Geometry and Features

Bullet geometry encompasses the ogive, body, and base configurations that determine aerodynamic efficiency, stability, and accuracy. The ogive, the curved nose section from the tip to the shank, is critical for reducing drag and maintaining flight stability. Tangent ogives feature a smooth radius that meets the bullet body tangentially, promoting consistent precision due to less sensitivity to seating depth variations, though they typically yield lower ballistic coefficients (BC) compared to secant designs. Secant ogives, with a sharper radius intersecting the body at an angle, optimize aerodynamics for higher BC values, enhancing long-range performance by minimizing drag, but require precise chamber throat alignment to avoid inconsistencies in jump distance. Hybrid ogives blend tangent and secant elements, aiming to combine precision with improved BC, as seen in designs from manufacturers like Berger Bullets. Nose profiles vary by application: spitzer (pointed) noses reduce frontal area for better in bullets, while round-nose designs increase drag but feed reliably in tubular magazines. Hollow-point noses incorporate cavities that promote expansion upon impact, prioritizing terminal effects over pure ballistics, though they may slightly degrade BC. The , or flat tip diameter, influences drag; smaller meplats on match bullets minimize turbulence for sustained velocity. The bullet body is generally cylindrical to maximize bearing surface contact with the barrel, ensuring consistent engraving and minimal yaw. Base geometry affects rear drag: flat bases suffice for short-range use, but boat-tail bases taper rearward to reduce base pressure drag, improving BC by 10-20% in high-velocity projectiles, as verified in wind tunnel tests. Overall, optimized geometry enhances gyroscopic stability, requiring barrel twist rates matched to bullet length—for instance, a 1:10 twist stabilizes heavier .308 Winchester bullets—while deviations can induce wobble or keyholing. These features directly impact external ballistics, with secant boat-tail designs achieving BCs exceeding 0.6 in .30-caliber match bullets for reduced wind drift and flatter trajectories.

Propulsion and Casing

The cartridge case encases the primer, , and bullet, ensuring containment of gases and facilitating extraction after firing. Primarily manufactured from cartridge , an of 70% and 30% , the case exhibits high , enabling it to expand radially under peak chamber pressures—often exceeding 50,000 psi in cartridges—to form a gas-tight seal against the chamber walls, a known as . This expansion prevents rearward gas leakage while the forward force propels the bullet, after which the case contracts upon cooling for reliable extraction by the firearm's mechanism. Alternative materials include , often polymer-coated for improved extraction, and hybrid designs combining metal bases with bodies to reduce weight, though remains dominant for its balance of strength, resistance, and reloadability. Propulsion derives from the controlled of smokeless packed within the case, ignited by the primer's flash. The primer, embedded in the case head, contains a primary such as or , which detonates upon impact from the , generating heat to initiate the 's . Modern small arms s are predominantly single-base formulations of , providing consistent burn rates tailored to barrel length and , or double-base variants incorporating for enhanced energy density in higher-velocity applications. This rapid gas expansion, converting to kinetic force, accelerates the bullet through the barrel, with grain —such as flakes, cylinders, or spheres—dictating burn progression to maintain uniform curves and minimize . Case influences efficiency by optimizing volume for capacity and headspace for ignition reliability, with bottleneck shapes common in to accommodate larger charges relative to bullet diameter.

Materials and Production Techniques

Bullets primarily utilize lead for cores due to its of 11.34 g/cm³, which maximizes and for effective range and penetration, combined with malleability that facilitates expansion or fragmentation upon target impact. Lead alloys, often incorporating for hardness, are standard in non-jacketed designs to reduce barrel leading while maintaining deformability. Steel cores provide enhanced penetration at lower cost but limited expansion, commonly used in full metal jacket ammunition; denser alternatives like or achieve superior armor-piercing performance through higher specific gravity. Jackets encase the core to enable higher muzzle velocities without lead deposition in rifled barrels, typically composed of (pure or alloyed) for its and thermal conductivity, preventing jacket separation under acceleration. , a 95% -5% , predominates in bullets for optimal into grooves; alternatives include , aluminum for lighter weight, or for resistance in specialized loads. Monolithic bullets, machined entirely from or , eliminate core-jacket interfaces, reducing inconsistency in yaw or fragmentation for precision applications. Frangible variants employ compressed metal powders, often or , bonded without binders to disintegrate on hard surfaces, minimizing risks. Production begins with core formation: involves melting lead alloys at approximately 327°C and pouring into multi-cavity molds, followed by and sizing to achieve tolerances of ±0.001 inches for projectiles. compresses lead slugs or wire via hydraulic presses through dies, yielding uniform density without , ideal for jacketed bullets requiring velocities exceeding 2,500 fps. Jackets are deep-drawn from metal cups, annealed, and formed around the core using progressive dies, with final assembly via or bonding to ensure concentricity below 0.0005 inches for match-grade accuracy. Advanced techniques employ CNC machining from for custom or monolithic bullets, turning diameters to sub-0.0001-inch precision and applying grooves for controlled expansion. sinters frangible cores at 800-1000°C under inert atmosphere, pressing powders at 30-50 tons per to form brittle matrices that shatter on impact rather than penetrate. applies thin copper layers (0.001-0.005 inches) over lead cores via electrolytic deposition in acidic baths, offering a cost-effective jacket substitute for low-velocity loads while minimizing . integrates gauging and ballistic testing to verify weight variations under 0.1% and velocity spreads below 15 fps.

Types and Variants

Standard Construction Types

Standard bullet constructions primarily encompass unjacketed lead projectiles and jacketed designs featuring a core encased in a metallic sheath. Unjacketed bullets utilize lead or lead-antimony-tin alloys without an outer covering, produced through or methods to achieve desired shape and hardness. These types predominate in low-velocity or cost-sensitive applications, such as muzzleloaders and reloaded . Cast lead bullets form by pouring molten —often comprising 90-95% lead, 2-6% for hardness, and trace tin—into precision molds, followed by cooling, extraction, sizing, and lubrication. This process yields economical projectiles suitable for black powder rifles and pistols, though potential imperfections like voids or surface irregularities can affect uniformity compared to other methods. Swaged unjacketed bullets, conversely, emerge from compressing pure or soft lead (Brinell hardness 5-6) via high-pressure dies acting on wire or pellets, producing dense, consistent forms without . This cold-forming technique minimizes oxidation, enhances roundness, and supports applications in airguns or reduced-power loads where leading must be avoided. Jacketed constructions, ubiquitous in centerfire and cartridges since the late , pair a ductile lead-alloy core with a jacket of (95% , 5% ) or to mitigate barrel and ensure reliable cycling. Manufacturing entails drawing into cups, inserting the core, and the assembly for final geometry, with the jacket preventing core deformation under high velocity. The (FMJ) represents a baseline jacketed variant, wherein the sheath fully envelops the core except at the exposed base, optimizing penetration and feed reliability in and rounds. FMJ bullets exhibit minimal expansion on impact due to the enclosing , aligning with conventions like the 1899 Hague Declaration for lawful wartime use, while reducing lead vaporization in sustained fire.

Specialized and Purpose-Built Bullets

Specialized and purpose-built bullets incorporate distinct compositions or structures to deliver effects beyond conventional penetration and expansion, such as defeating armor, illuminating trajectories, igniting targets, or fragmenting to limit secondary hazards. These designs prioritize tactical or training objectives, often integrating , hardened cores, or brittle alloys while adhering to ballistic stability. Armor-piercing bullets employ a dense, hardened core—typically , , or —sheathed in a ductile to concentrate impact energy and breach , vehicle plating, or barriers without deforming prematurely. Early iterations, like the 1860s Palliser chilled-iron shots for naval guns, evolved into small-arms variants by , with modern and calibers regulated under U.S. law to restrict civilian access for cores exceeding specific thresholds in jacketed designs. Tracer bullets embed a pyrotechnic mixture, often or magnesium compounds, in the base, ignited by gases to emit a luminous or streak visible during flight, facilitating real-time observation and fire adjustment in low-visibility conditions. Military forces deploy them at ratios like one tracer per five rounds to conserve composition while marking point of impact; infrared variants minimize detection for night operations. Incendiary bullets integrate a chemical , such as or derivatives, that activates on impact to generate intense heat and ignite fuels, fabrics, or structures, amplifying terminal effects against soft or flammable targets. Combined in hybrid forms like armor-piercing incendiary-tracer, they have seen use in aerial and anti-materiel roles, though small-arms applications remain limited by Convention restrictions on indiscriminate fire. Frangible bullets, formed from compressed metal powders like copper-tin alloys without lead binders, pulverize into non-penetrating fragments upon hitting rigid surfaces, curtailing ricochets and over-penetration in confined spaces. Developed for close-quarters battle training since the mid-20th century, they enable safe force-on-force drills and reduce range cleanup hazards, though their lower mass yields reduced velocity and energy compared to monolithic projectiles.

Caliber-Specific Categories

Bullets are engineered to match the precise and performance requirements of specific calibers, influencing factors such as , energy transfer, and . Calibers are broadly classified into , , and specialized categories, with bullet designs optimized for each group's typical muzzle velocities and intended applications; for instance, handgun bullets prioritize rapid expansion at lower speeds (around 1,000-1,200 fps), while rifle bullets emphasize penetration and stability at higher velocities (2,000-3,000 fps). These categories reflect empirical ballistic data showing that smaller calibers achieve effectiveness through high and , whereas larger ones rely on greater mass for . Handgun calibers, ranging from .22 to .45 inches, dominate civilian and uses, with bullets typically weighing 50-230 grains. The 9mm (0.355-inch ) is the most prevalent, using 115-147 grain projectiles in (FMJ) for training or jacketed (JHP) for expansion upon impact, delivering approximately 300-400 foot-pounds of at 1,100 fps. Larger pistol calibers like (0.452-inch, 185-230 grains) prioritize through wider wound channels, with historical data from FBI tests indicating superior one-shot incapacitation rates compared to smaller 9mm loads, though modern bonded JHP designs have narrowed this gap via improved penetration (12-18 inches in ). Other common variants include (0.355-inch, 90-100 grains) for compact carry and (0.400-inch, 135-180 grains), which balances recoil and capacity but shows higher overpenetration risks in urban scenarios per NIJ standards. Rifle calibers span small-bore (.17-.22 inches) for , intermediate (5.56mm/.223, 0.224-inch) for tactical roles, and full-power (.30-.50 inches) for long-range precision. Small-bore .22 LR (0.223-inch, 30-40 grains) excels in low-recoil and small game, achieving 1,000-1,300 fps with minimal tissue disruption suitable for . Intermediate 5.56x45mm bullets (55-77 grains) fragment at velocities over 2,700 fps, as evidenced by U.S. military wound profiles from Vietnam-era studies showing yaw-induced for enhanced lethality. Larger calibers like /7.62x51mm (0.308-inch, 150-180 grains) deliver 2,500 fps and 2,500 foot-pounds, with boat-tail (BTHP) designs optimizing for 800-yard , supported by ballistic coefficients above 0.4 in empirical drag tests.
Caliber CategoryExample CalibersBullet Diameter (inches)Typical Weight (grains)Key Ballistic Traits
Handgun9mm, 0.355-0.452115-230Expansion-focused; 300-500 ft-lbs energy; short-range (50 yards max).
Small Rifle.22 LR, .223/5.560.22330-77High velocity (1,000-3,000 fps); fragmentation in intermediates.
Large Rifle, .30-060.308-0.308150-220High mass; deep penetration; 2,000+ ft-lbs for 500+ yards.
Specialized calibers, such as (0.510-inch, 600-800 grains) for anti-materiel roles, feature armor-piercing or incendiary cores to defeat barriers, with muzzle energies exceeding 12,000 foot-pounds verified in military testing. In military classifications, calibers under 20mm encompass most and bullets, prioritizing controllability and logistics over raw power. Bullet selection within categories must account for twist rates—e.g., 1:7 inches for stabilizing 62-grain 5.56mm—to prevent keyholing and ensure accuracy, as demonstrated in and gel-block experiments.

Applications

Military and Tactical Employment

Military forces predominantly employ (FMJ) bullets in ammunition to comply with the 1899 Hague Declaration, which prohibits the use of bullets designed to expand or flatten easily in the during international armed conflicts. This design features a soft lead core encased in a harder metal jacket, typically or , promoting deep straight-line penetration rather than rapid energy dump via expansion. FMJ construction ensures reliable feeding in automatic and semi-automatic firearms, reduces barrel compared to unjacketed lead, and supports high-volume due to lower . In tactical operations, FMJ bullets serve core roles in and fire, emphasizing volume of fire, penetration through light cover, and sustained suppressive effects. For instance, the U.S. M855 cartridge, with a 62-grain FMJ launched at approximately 3,000 feet per second from a 20-inch barrel, achieves effective ranges up to 500 meters while yawing or fragmenting upon impact at high velocities to enhance tissue disruption. This ballistic profile supports point-target engagement in assault rifles like the and area suppression via squad automatic weapons such as the M249 SAW, where over-penetration risks are managed through shot placement discipline rather than inherent bullet expansion. Empirical wound ballistics data indicate that FMJ rounds produce narrower permanent cavities than expanding types but generate significant temporary cavitation from , with effectiveness hinging on velocity retention—below 2,500 feet per second, fragmentation diminishes, potentially prolonging incapacitation times. Specialized FMJ variants augment standard ball for targeted tactical needs: armor-piercing (AP) cores with or penetrators defeat and barriers; tracers incorporate incendiary compounds for trajectory visualization and fire adjustment in low-light or night operations; and match-grade FMJ optimizes precision for systems, achieving sub-MOA accuracy at extended ranges. In combat analyses, such as those from and engagements, FMJ-dominant loads have demonstrated reliable lethality through multiple hits, though critics note inconsistent one-shot stops due to limited expansion, prompting doctrinal shifts toward higher-velocity calibers like the emerging 6.8×51mm for improved terminal performance against protected threats. Overall, selection prioritizes logistical uniformity and legal adherence over maximal per-shot incapacitation, with tactical efficacy derived from marksmanship, , and integration with rather than bullet design alone.

Civilian and Hunting Uses

Bullets employed in hunting are designed to maximize terminal ballistics for ethical harvesting of game, prioritizing rapid incapacitation through controlled expansion and sufficient penetration to reach vital organs. Soft-point and hollow-point configurations facilitate mushrooming upon impact, increasing the temporary and permanent wound cavity diameters to enhance energy dump and hemorrhage, as evidenced by radiographic analyses showing distinct fragmentation patterns in lead-core versus monolithic copper designs. Studies on big game indicate that copper bullets achieve comparable killing efficiency to lead-based ones, with similar post-shot flight distances in deer, underscoring effective tissue disruption independent of material when velocity and construction match. Hunting bullet categories include cup-and-core for versatile medium game like deer, bonded cores to retain mass during expansion for tougher hides, partitioned designs separating expansion and penetration functions, and monolithic solids for deep penetration in large or dangerous game. Popular calibers for North American , such as and , deliver kinetic energies exceeding 1,500 foot-pounds at 300 yards, enabling reliable performance across ranges typical for ethical shots under 400 yards. In civilian recreational applications, bullets serve target practice, , and competitive disciplines like benchrest or , favoring full metal jacket or cast lead variants for feeding reliability in pistols and , cost efficiency, and minimal barrel fouling during high-volume . These uses emphasize accuracy and consistency over terminal effects, with empirical range data highlighting reduced lead exposure risks through proper ventilation and non-lead alternatives in indoor facilities. Annual U.S. participation in organized exceeds 20 million rounds fired in competitions, underscoring bullets' role in skill development without game-specific optimizations.

Self-Defense Efficacy

The efficacy of bullets in scenarios hinges primarily on their ability to rapidly incapacitate a through physiological disruption, such as to the or massive blood loss from vital organ hits. bullets, the most common in civilian , produce wounding effects via , permanent cavity size, temporary , and fragmentation, but these are limited compared to rounds due to lower and . The Federal Bureau of Investigation's analysis identifies penetration as the paramount factor, recommending 12 to 18 inches in to ensure reach of vital structures while minimizing overpenetration risks. Shot placement outweighs caliber differences in achieving stops, as empirical reviews of real-world shootings indicate that hits to the or upper yield near-instant incapacitation regardless of bullet type, while torso hits often require multiple rounds due to adrenaline-fueled persistence. Analyses of over 1,800 documented encounters show one-shot torso stops occurring in approximately 30-60% of cases depending on , but these figures derive from selective datasets criticized for incomplete incapacitation definitions and failure to control for variables like drug influence or motivation. Larger s like exhibit marginally higher one-shot stop rates (around 90% in proponent studies) over 9mm (around 75-80%) due to greater tissue displacement, yet modern 9mm hollow-point loads achieve comparable penetration and expansion, enabling higher capacity and better controllability under stress. Expanding hollow-point bullets enhance self-defense efficacy by mushrooming on impact to create wider channels and transfer more efficiently than full metal jacket (FMJ) rounds, which often pass through with minimal deformation and higher risk of collateral injury. FBI protocol shifted in favor of jacketed hollow points after the 1986 shootout, where FMJ overpenetration and inadequate stopping contributed to agent casualties, prompting emphasis on bullets that reliably expand to 1.5 times diameter while penetrating sufficiently. In civilian contexts, such ammunition reduces bystander hazards in urban settings, though failures occur if expansion is impeded by barriers like clothing. Overall, no bullet guarantees immediate cessation of , with studies reporting averages of 2-3 rounds to incapacitate determined attackers, underscoring the need for training in rapid, accurate follow-ups over reliance on "" myths. Psychological stops from visible injury play a role but are unpredictable, reinforcing that efficacy stems from consistent hits to high-threat zones rather than caliber alone.

International Agreements and Prohibitions

The primary international agreement prohibiting specific types of bullets is the 1899 Declaration concerning Expanding Bullets (Declaration IV,3), adopted on July 29, 1899, during the First Peace Conference. This declaration stipulates that contracting parties "agree to abstain from the use of bullets which expand or flatten easily in the ," targeting designs such as dum-dum bullets, which feature soft or hollowed lead tips intended to mushroom upon impact. Initially ratified by 16 states, the declaration reflects early codification of customary (IHL) principles against weapons causing superfluous injury or unnecessary suffering beyond that required for incapacitation. It applies exclusively to international armed conflicts and forces, permitting (FMJ) bullets as compliant alternatives, which penetrate without significant deformation. The declaration's language of "abstain" rather than outright prohibition frames it as an measure, where states voluntarily forgo certain ammunition in warfare while retaining production rights for uses. Compliance has been near-universal among modern militaries, though enforcement relies on customary IHL, extending the norm to non-signatories in international conflicts. Exceptions or debates arise in non-international armed conflicts, where the rule's applicability is less settled, and expanding bullets like hollow points remain standard for due to reduced overpenetration risks. Separate prohibitions address exploding bullets, rooted in the 1868 St. Petersburg Declaration, which banned explosive projectiles weighing less than 400 grams—encompassing most small-arms ammunition—to prevent excessive fragmentation injuries. This evolved into customary IHL Rule 78, which forbids the anti-personnel use of bullets designed to explode within the , such as those with internal detonators, as they inflict wounds disproportionate to legitimate military aims. Unlike expanding bullets, exploding variants are rare in conventional forces but prohibited to uphold distinctions between combatants and civilians. Broader frameworks like the 1980 (CCW) do not directly regulate bullet types but influence through protocols on indiscriminate effects; however, they focus on systems like cluster munitions rather than individual projectiles. Recent UN efforts, such as the 2025 Global Framework for Through-life Conventional Management adopted by the General Assembly, emphasize marking, tracing, and for all types but impose no design-specific bans. Customary IHL also prohibits bullets rendered poisonous or infected, reinforcing baseline restrictions without targeting standard constructions. These agreements collectively prioritize minimization in warfare while allowing bullets optimized for reliable incapacitation.

National Laws and Second Amendment Considerations

Federal law, primarily through the (18 U.S.C. § 922 et seq.), regulates the interstate commerce, manufacture, importation, and possession of , including bullets, but imposes fewer restrictions on retail purchases than on firearms. Unlike firearms sales by licensed dealers, which require via the National Instant Criminal Background Check System (NICS), there is no federal mandate for on ammunition purchases from private sellers or at point-of-sale for most transactions, though prohibited persons—such as convicted felons, fugitives, unlawful drug users, and those adjudicated as mentally defective—face a blanket ban on possessing any under 18 U.S.C. § 922(g)(1)-(9). This prohibition extends to both firearms and , reflecting congressional intent to prevent access by high-risk individuals, as affirmed in cases upholding the statute's constitutionality for those categories. Age-based restrictions further limit access: prohibits licensed dealers from selling to persons under 21 and to those under 18 (18 U.S.C. § 922(b)(1)), with exceptions for certain lawful activities like or target practice under adult supervision. Specialized faces targeted bans, such as the prohibition on manufacturing, importing, or selling armor-piercing bullets capable of penetrating , unless for government or use (18 U.S.C. § 921(a)(17)(B); Law Enforcement Officers Protection Act of 1986). The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) oversees licensing for manufacturers, importers, and dealers engaged in interstate commerce, requiring compliance with marking, record-keeping, and export controls, though recent 2025 rulings have eased import restrictions on certain non-lethal training rounds not classified as . These regulations aim to curb trafficking and illegal possession without broadly restricting civilian access to standard bullets for lawful purposes. The Second Amendment's protection of the right to keep and bear arms, as interpreted by the Supreme Court in District of Columbia v. Heller (2008), encompasses not only firearms but also the ammunition essential to their functional use for self-defense and other traditionally lawful activities. The Court emphasized that longstanding prohibitions on possession by felons and the mentally ill are presumptively lawful, but regulations that effectively nullify the right—such as outright bans on common ammunition—would infringe it, as arms without bullets are inoperable. Subsequent rulings like New York State Rifle & Pistol Association v. Bruen (2022) applied a history-and-tradition test to gun laws, leading lower federal courts to invalidate some state-level ammunition restrictions (e.g., mandatory background checks or purchase limits) for lacking historical analogues, while upholding federal categorical bans on prohibited persons as consistent with founding-era disarming of dangerous individuals. No Supreme Court decision has directly struck down federal ammunition laws, but ongoing challenges, including those involving indicted persons' access under 18 U.S.C. § 922(n), underscore tensions between regulatory aims and the Amendment's core protections. As of 2025, federal policy prioritizes targeted restrictions over universal controls, reflecting judicial deference to laws with historical precedents amid debates over expanding background checks for ammo sales.

Controversies and Empirical Analysis

Prevalent Myths and Debunkings

One prevalent myth asserts that bullets possess sufficient to knock a backward upon impact, as frequently depicted in media. In reality, this effect does not occur due to conservation of momentum under Newton's Third Law, which would equally recoil the shooter—an outcome not observed in ballistic testing or forensic evidence. Wound studies confirm that even high-velocity rounds fail to displace an average adult significantly, with any perceived movement attributable to psychological or muscular reactions rather than projectile force. Another common misconception holds that bullets, particularly high-velocity ones, tumble chaotically or bounce extensively within tissue, creating unpredictable wound channels. Empirical analysis of gunshot pathology reveals that bullets typically follow a relatively straight path upon entering , with potential yawing or pitching occurring deeper in the body under specific conditions like velocity exceeding 2,000 feet per second, but without extensive fragmentation unless designed for it (e.g., certain hollow-points). This behavior is corroborated by data and tests, showing that tissue density and impact angle influence trajectory more than inherent instability, debunking notions of bullets "ricocheting" internally as Hollywood exaggerations. The belief that bullets fired celebratorily into the air pose no danger upon descent, reaching only harmless , is also widespread. Falling bullets can attain speeds of 200–300 feet per second—sufficient to penetrate skulls or cause fatal injuries—as documented in epidemiological studies of incidents, with over 100 U.S. deaths attributed to such events since 1985, often during holidays. Physics calculations and forensic reconstructions indicate that aerodynamic shape limits below muzzle speed but not below lethality thresholds for small-caliber projectiles like 9mm or . Claims that larger-caliber bullets are inherently more lethal than smaller ones, regardless of shot placement, persist despite evidence prioritizing hit location and quantity over diameter. Ballistic research emphasizes that incapacitation correlates more with disruption of vital structures (e.g., or major vessels) than sheer size, as smaller rounds like 5.56mm can achieve comparable or superior terminal effects through fragmentation or yaw when striking vitals, per wound profiles from conflicts like . This is evidenced by comparative studies showing no universal "" advantage for calibers above 9mm in contexts, where multiple precise hits outperform single large impacts. Hollow-point bullets are often misrepresented as uniformly prone to failure in expansion, leading to overpenetration akin to (FMJ) rounds, or conversely as excessively fragmenting to cause gratuitous harm. Modern jacketed hollow-points reliably expand in at handgun velocities (900–1,200 fps), reducing penetration depth to 12–18 inches—optimal for vital organ damage without excessive exit risks—outperforming FMJ in FBI protocol tests by minimizing collateral threats. While barriers like clothing can inhibit expansion in 10–20% of cases, forensic data from shootings affirm their efficacy in over FMJ, countering myths rooted in early unreliable designs rather than contemporary . Regarding rifle rounds like 5.56mm, a myth suggests they are engineered to tumble immediately upon tissue entry for exaggerated wounding, violating international conventions or prioritizing maiming over lethality. In truth, yaw and potential fragmentation occur post-impact due to the bullet's length-to-diameter ratio and high velocity destabilizing it in dense media, a phenomenon not unique to 5.56mm but shared with spitzer designs in 7.62mm or .30-06, as validated by U.S. Army wound ballistics reports from Aberdeen Proving Ground. This effect enhances energy transfer without deliberate "wounding" intent, aligning with Hague Convention allowances for non-expanding military projectiles, and high-velocity impacts often prove rapidly fatal via hydrodynamic shock rather than prolonged incapacitation.

Debates on Effectiveness and Lethality

The of bullets in incapacitating is debated primarily through the lens of , focusing on penetration, permanent wound cavity volume, and energy transfer to tissue, with empirical studies emphasizing that reliable physiological stops require disruption of major vessels, heart function, or the rather than mere deposition. The FBI's 1989 Handgun Wounding Factors and , based on tests and autopsy analyses, concluded that bullets (typically 9mm to ) produce minimal temporary cavitation insufficient for rapid incapacitation, prioritizing 12-18 inches of penetration in simulated muscle tissue to ensure vital organ damage over expansion or fragmentation alone. This contrasts with earlier notions of "" propagated in some hunting literature, which the report dismisses as negligible for handgun velocities below 1,200 fps, supported by high-speed radiographic showing limited remote tissue disruption. Proponents of metrics, such as Evan Marshall and Ed Sanow's compilations from police shooting reports (1980s-2000s), claimed one-shot incapacitation rates exceeding 90% for hollow points versus under 60% for 9mm FMJ, attributing differences to larger diameters and . However, these statistics face substantial critique for —drawing disproportionately from torso hits at close range without verifying shot placement, distance, or attacker variables like use—and failure to distinguish psychological surrender from physiological failure, as noted in peer-reviewed reviews and wound ballistics analyses by experts like Martin Fackler, who argued such data inflates caliber superiority without controlled variables. Empirical data from over 1,800 urban shootings (aggregated in independent analyses) indicate average hits-to-stop ratios of 2-3 for handguns regardless of , with outliers explained by impacts rather than bullet mass or energy. In military rifle contexts, lethality debates contrast 5.56x45mm 's reliance on high-velocity yawing and fragmentation for wound enhancement—effective within 200 meters per U.S. Army close-quarters battle studies showing 80-90% incapacitation via multiple hits—with its diminished performance against barriers or at extended ranges due to insufficient penetration, as evidenced in post-2001 data where unfragmented rounds produced narrow channels akin to ice pick . The heavier 7.62x51mm offers superior consistent tissue crush and barrier defeat (e.g., 2-3 times the penetration depth in ), but NATO evaluations from the 1980s highlighted trade-offs in soldier fatigue and ammunition carriage, with metrics favoring volume of fire over per-round "," a the same studies label mythical absent central hits. empirical evidence, including Vietnam-era analyses, underscores that no small-arms bullet guarantees one-shot , with survival post-torso hits often exceeding 90% without rapid medical intervention, modulated by factors like hemorrhage control and individual physiology. These debates reveal systemic challenges in quantifying lethality, as — including , motivation, and intoxicants—overrides ballistic models, prompting recommendations for multiple precise shots over caliber obsession, per FBI and protocols updated through 2020s testing.

Broader Societal and Ethical Realities

Bullets, as components of , facilitate both lethal aggression and defensive responses in , contributing to empirical patterns of violence and protection. In the United States, were involved in approximately 47,000 deaths in 2023, with suicides comprising over half and accounting for about 43%, yielding a rate roughly 26 times higher than in other high-income nations. These incidents impose substantial economic burdens, estimated at $557 billion annually, encompassing medical costs, lost , and taxpayer-funded expenditures of $12.62 billion. Defensive uses of , however, occur frequently, with surveys indicating 500,000 to 3 million instances per year where bullets deter or halt threats without firing, though underreporting in official data like the Archive's 1,217 recorded cases in 2023 suggests higher actual figures derived from victimization surveys. Such dual roles underscore causal complexities: widespread bullet availability correlates with elevated risks in urban settings but also empowers individual resistance to , as evidenced by analyses showing used defensively far outnumbering criminal applications in certain estimates. Ethically, the deployment of bullets embodies tensions between the right to preserve life through proportionate lethal force and imperatives to minimize superfluous harm. Principles of , rooted in natural rights and codified in laws like stand-your-ground statutes, permit bullet use when imminently facing death or grave injury, prioritizing the defender's survival over the aggressor's, as transfer from bullets ensures rapid incapacitation essential for halting ongoing threats. In military contexts, the 1899 Declaration prohibits expanding bullets—such as dum-dum variants—for causing unnecessary suffering by fragmenting within tissue, reflecting a humanitarian that warfare should disable combatants efficiently without exacerbating wounds beyond tactical necessity. This distinction informs ethics: hollow-point bullets, ethically favored for self-defense due to reduced overpenetration risks to bystanders, contravene Hague norms in war, highlighting context-dependent morality where bullet design balances lethality with collateral minimization. Critics of broad prohibitions argue they overlook empirical realities of threat dynamics, where non-expanding bullets may prolong engagements and increase overall casualties, while proponents emphasize universal restraints on suffering absent overriding defensive imperatives.

References

  1. https://nij.ojp.gov/nij-hosted-online-training-courses/firearms-examiner-training/module-03/ammunition
  2. https://nij.ojp.gov/nij-hosted-online-training-courses/firearms-examiner-training/module-10/physical-features
  3. https://science.howstuffworks.com/10-bullet-innovations.htm
  4. https://blacksheepammo.com/blog/the-evolution-of-ammunition-from-musket-balls-to-modern-bullets/
  5. https://www.berrysmfg.com/17-different-types-of-bullets-and-their-uses/
  6. https://www.5dtactical.com/blog/quick-guide-to-bullet-types/
  7. https://rkba.org/guns/principles/definitions/ammunition.html
  8. https://www.uslawshield.com/ammunition-101/
  9. https://www.hunter-ed.com/pennsylvania/studyGuide/Basic-Components-of-Ammunition/20103901_88399/
  10. https://www.tncourts.gov/sites/default/files/docs/firearmshandout_1.pdf
  11. https://nij.ojp.gov/nij-hosted-online-training-courses/firearms-examiner-training/module-10/composition
  12. https://illumin.usc.edu/ballistics-of-modern-firearms/
  13. https://www.hornady.com/bullets/anatomy-of-a-bullet
  14. https://webpath.med.utah.edu/TUTORIAL/GUNS/GUNBLST.html
  15. https://mauigun.com/how-do-guns-work/
  16. http://www.enfield-rifles.com/basic-ballistics_topic3346.html
  17. https://nij.ojp.gov/nij-hosted-online-training-courses/firearms-examiner-training/module-08/cycle-fire-steps
  18. https://apps.dtic.mil/sti/tr/pdf/AD0462060.pdf
  19. https://www.sciencedirect.com/science/article/pii/S2214914724001120
  20. https://hypertextbook.com/facts/2003/MichaelTse.shtml
  21. https://www.hornady.com/team-hornady/ballistic-information/ballistic-resources/internal-ballistics
  22. https://www.bhu.ac.in/Content/Syllabus/Syllabus_300620200513010858.pdf
  23. https://www.suncam.com/miva/downloads/docs/402.pdf
  24. https://apps.dtic.mil/sti/tr/pdf/AD0830264.pdf
  25. https://appliedballisticsllc.com/wp-content/uploads/2021/06/Aerodynamic-Drag-Modeling-for-Ballistics.pdf
  26. http://ffden-2.phys.uaf.edu/webproj/211_fall_2020/Ethan_Hoover/rifling-and-ballistics.html
  27. https://www.fieldandstream.com/stories/guns/rifles/understanding-importance-of-bullet-trajectory
  28. https://pmc.ncbi.nlm.nih.gov/articles/PMC9462949/
  29. https://apps.dtic.mil/sti/tr/pdf/ADA221395.pdf
  30. https://tirotactico.net/wp-content/uploads/2016/07/handgun-wounding-factors-and-effectivene-special-agent-urey-w-patrick.pdf
  31. https://viperweapons.us/blog/f/the-human-target
  32. https://www.rkba.org/research/fackler/wrong.html
  33. https://www.omnicalculator.com/physics/muzzle-velocity
  34. https://www.sciencing.com/calculate-muzzle-velocity-7669736/
  35. https://www.sciencing.com/calculate-bullet-trajectory-5185428/
  36. https://.org/books/university-physics-volume-1/pages/4-3-projectile-motion
  37. http://ffden-2.phys.uaf.edu/webproj/211_fall_2018/David_Atwood/david_atwood/gravity.html
  38. https://www.remington.com/big-green-blog/what-is-a-ballistic-coefficient.html
  39. http://nennstiel-ruprecht.de/bullfly/ballcoeff.htm
  40. https://thenorthernhunter.com/2022/12/02/environmental-effects-on-bullet-trajectory/
  41. https://stealthvision.com/how-does-altitude-affect-bullet-trajectory/
  42. https://grizzlycartridge.com/what-can-affect-the-performance-of-a-bullet/
  43. https://www.longrangehunting.com/threads/elevation-effects-on-bullet-trajectory.262504/
  44. https://tacticon.com/shooting-skills/external-ballistics/
  45. http://www.vikingsword.com/vb/showthread.php?t=13586
  46. https://www.nramuseum.org/gun-info-research/a-brief-history-of-firearms.aspx
  47. https://americanhistory.si.edu/explore/stories/hand-cannon-very-early-and-heavy-firearm
  48. https://shop.otmtactical.com/The-History-of-Ammunition-The-First-Bullet.html
  49. https://gunownersradio.com/why-do-we-still-use-lead-bullets/
  50. http://firearmshistory.blogspot.com/2010/06/bullets-early-bullets.html
  51. https://crateclub.com/blogs/loadout/understanding-the-size-and-impact-of-musket-balls-how-big-is-a-musket-ball
  52. https://www.forbes5.pitt.edu/article/production-muskets-and-their-effects-eighteenth-century
  53. https://www.battlefieldstrust.com/media/762.pdf
  54. http://albrechts.se/handgonnes-and-cannons-of-the-middle-ages/
  55. https://srv-a.bcm.nl/why-lead-is-used-in-bullets-a-deep-dive-into-the-history-properties-and-considerations/
  56. https://www.historynet.com/minie-ball/
  57. https://pjthorndyke.wordpress.com/2015/03/30/inventions-and-discoveries-of-the-19th-century-3-firearms/
  58. https://www.pritzkermilitary.org/explore/museum/past-exhibits/dignity-duty-journals-erasmus-corwin-gilbreath/minie-ball
  59. https://cupola.gettysburg.edu/cgi/viewcontent.cgi?article=1417&context=compiler
  60. https://www.historynet.com/top-ten-19th-century-weapons/
  61. https://www.scribd.com/presentation/425550922/Forensic-Ballistic-pptx
  62. https://reloader.com/2025/06/rifle-bullets-by-any-other-name-spitzer-spire-point-boattail-vld-eld/
  63. https://www.rifleshootermag.com/editorial/20th-century-german-military-arms/83390
  64. https://www.historicalfirearms.info/post/72807262505/the-spitzer-round-until-the-beginning-of-the-20th
  65. https://proarmory.com/blog/comparisons/fmj/
  66. https://www.quora.com/When-was-tracer-ammo-first-used
  67. https://www.iwm.org.uk/collections/item/object/30026574
  68. https://www.americanrifleman.org/content/back-to-basics-pistol-bullets/
  69. https://www.berrysmfg.com/types-of-hollow-point-bullets/
  70. https://www.gunsandammo.com/editorial/changes-in-cartridges/367929
  71. https://sadefensejournal.com/ammunition-advances-an-in-depth-review/
  72. https://www.darpa.mil/news/2015/exacto-guided-bullet-demonstration
  73. https://www.darpa.mil/research/programs/extreme-accuracy-tasked-ordnance
  74. https://spectrum.ieee.org/darpas-selfsteering-bullets-home-in-on-moving-targets
  75. https://www.americanhunter.org/content/is-lead-ammo-dead/
  76. https://www.sciencedirect.com/science/article/pii/S0048969723049136
  77. https://wildbeimwild.com/en/denmark-is-the-first-country-to-introduce-a-complete-ban-on-lead-ammunition/
  78. https://www.all4shooters.com/en/hunting/ammunition/lead-free-and-leaded-ammunition-for-hunting-considerations-situation-switzerland/
  79. https://themagshack.com/current-trends-in-ammunition/
  80. https://bisresearch.com/insights/the-future-of-small-caliber-ammunition-through-innovation-and-sustainability
  81. https://www.nrafamily.org/content/what-is-an-ogive-profile/
  82. https://appliedballisticsllc.com/wp-content/uploads/2021/06/Characteristics-of-Different-Bullet-Ogive-Designs.pdf
  83. https://www.accurateshooter.com/ballistics/tangent-vs-secant-vs-hybrid-ogive-bullets/
  84. https://bergerbullets.com/nobsbc/form-factor/
  85. https://bergerbullets.com/nobsbc/how-bullet-geometry-affects-bc-consistency/
  86. https://bisonballistics.com/articles/barrel-twist-and-bullet-stability
  87. https://www.theballisticassistant.com/the-modern-cartridge-case/
  88. https://nij.ojp.gov/nij-hosted-online-training-courses/firearms-examiner-training/module-03/cartridge-cases
  89. https://www.americanrifleman.org/content/back-to-basics-cartridge-cases/
  90. https://www.explainthatstuff.com/bullets.html
  91. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/gun-propellant
  92. https://www.quora.com/What-propellants-do-we-use-in-our-bullets-today
  93. https://www.powdervalley.com/reloading-101/comparing-common-bullet-materials-copper-lead-steel/
  94. https://www.fieldandstream.com/outdoor-gear/guns/ammo/handgun-ammo/what-are-bullets-made-of
  95. https://www.gunfinder.com/articles/76057
  96. https://n1outdoors.com/types-of-ammunition/
  97. https://www.berrysmfg.com/plated-vs-jacketed-vs-cast-bullets/
  98. https://www.americanrifleman.org/content/making-ammo-a-behind-the-scenes-look/
  99. https://smartestworkers.com/how-bullets-are-made-inside-a-gun-factor-step-by-step-manufacturing-process-and-precision-engineering/
  100. https://www.berrysmfg.com/what-are-bullets-made-of/
  101. https://thefiringline.com/forums/showthread.php?t=376813
  102. https://nielsenspecialtyammo.com/pages/nielsen-specialty-ammo-pellets-vs-cast-bullets
  103. https://www.corbins.com/blog/swaging-101-1/how-to-swage-bullets-51
  104. https://www.army.mil/article/184704/a_green_machine_success
  105. https://www.gunsandammo.com/editorial/rifle-bullet-designs/359618
  106. https://www.natchezss.com/blog/full-metal-jacket-bullet
  107. https://www.thetruthaboutguns.com/beginners-guide-to-rifle-bullets-how-theyre-made-types-and-uses/
  108. https://www.nrawomen.com/content/know-your-ammo-specialty-ammunition
  109. https://www.wideners.com/blog/what-is-black-tip-ammo/
  110. https://www.nssf.org/wp-content/uploads/2018/12/ArmorPiercing.pdf
  111. https://www.globalsecurity.org/military/systems/munitions/frangible.htm
  112. https://www.usconcealedcarry.com/blog/defending-your-castle-home-defense-with-frangible-bullets/
  113. https://www.pewpewtactical.com/bullet-sizes-calibers-and-types/
  114. https://www.academy.com/expert-advice/handgun-calibers
  115. https://backfire.tv/chart-of-all-rifle-calibers-in-order-and-their-power/
  116. https://buckhorncliffs.com/ammunition-by-caliber/
  117. https://mikelimadba.substack.com/p/ammunition-classification-small-medium
  118. https://www.smallarmssurvey.org/sites/default/files/resources/SAS-HB-06-Weapons-ID-ch4.pdf
  119. https://ihl-databases.icrc.org/en/ihl-treaties/hague-decl-iv-3-1899
  120. https://avalon.law.yale.edu/19th_century/dec99-03.asp
  121. https://www.ammunitiontogo.com/lodge/full-metal-jacket-bullets/
  122. https://blog.primaryarms.com/guide/a-guide-to-tactical-rifle-cartridges/
  123. https://www.thearmorylife.com/the-evolution-of-u-s-military-rifle-cartridges/
  124. https://swiftsilentdeadly.com/dont-use-fmj-ammo-for-self-defense/
  125. https://silencerco.com/blog/military-calibers-a-historical-overview/
  126. https://blog.refactortactical.com/blog/277-sig-fury-ngsw/
  127. https://www.trueshotammo.com/academy/what-is-fmj-ammo-good-for/
  128. https://pmc.ncbi.nlm.nih.gov/articles/PMC6675795/
  129. https://www.researchgate.net/publication/331745706_Unleaded_hunting_Are_copper_bullets_and_lead-based_bullets_equally_effective_for_killing_big_game
  130. https://vortexoptics.com/blog/making-sense-of-bullet-types.html
  131. https://www.americanhunter.org/content/10-most-versatile-long-range-hunting-cartridges/
  132. https://www.gunsandammo.com/editorial/the-anatomy-of-a-hunting-bullet/472359
  133. https://ehjournal.biomedcentral.com/articles/10.1186/s12940-017-0246-0
  134. https://www.americanhunter.org/content/how-to-choose-the-right-hunting-bullet/
  135. https://www.gunnuts.net/wp-content/uploads/2020/06/FBI-9mm-white-paper-2014.pdf
  136. https://www.lfxtraining.com/articles/handguncaliber
  137. https://www.buckeyefirearms.org/alternate-look-handgun-stopping-power
  138. https://www.fieldandstream.com/stories/guns/handguns/handgun-stopping-power-truths
  139. https://www.ammunitiondepot.com/blog/why-hollow-points-are-the-best-choice-for-self-defense
  140. https://www.usconcealedcarry.com/blog/hollow-points-or-full-metal-jacket-for-concealed-carry/
  141. https://www.concealedcarry.com/gear/why-hollow-points-are-the-only-option-for-self-defense/
  142. https://spencerdurrant.com/2019/09/04/self-defense-is-stopping-power-a-myth/
  143. https://www.spartanfirearmstraininggroup.com/the-great-stopping-power-myth/
  144. https://www.cambridge.org/core/journals/international-review-of-the-red-cross/article/1899-hague-declaration-concerning-expanding-bullets-a-treaty-effective-for-more-than-100-years-faces-complex-contemporary-issues/49FAE61BF505D16B9740F495B8F7C4F1
  145. https://sadefensejournal.com/sost-a-way-forward-in-contemporary-understanding-of-the-1899-hague-declaration-on-expanding-bullets/
  146. https://www.diva-portal.org/smash/get/diva2:1635332/FULLTEXT01.pdf
  147. https://ihl-databases.icrc.org/en/customary-ihl/v1/rule78
  148. https://www.cambridge.org/core/books/customary-international-humanitarian-law/exploding-bullets-rule-78/C192C6C30FAD743867E3772D4B46BE9C
  149. http://disarmament.unoda.org/en/our-work/conventional-arms/legal-instruments/convention-certain-conventional-weapons
  150. https://docs.un.org/en/A/80/238
  151. https://opil.ouplaw.com/display/10.1093/law:epil/9780199231690/law-9780199231690-e447
  152. https://www.law.cornell.edu/uscode/text/18/922
  153. https://giffords.org/lawcenter/gun-laws/policy-areas/hardware-ammunition/ammunition-regulation/
  154. https://www.atf.gov/firearms/docs/ruling/atf-ruling-2025-2-importing-training-rounds/download
  155. https://supreme.justia.com/cases/federal/us/554/570/
  156. https://firearmslaw.duke.edu/2025/09/a-second-amendment-preview-of-the-supreme-courts-long-conference
  157. http://www.gwicu.com/Assets/Articles/Ballistics.pdf
  158. https://pubmed.ncbi.nlm.nih.gov/26982703/
  159. https://pmc.ncbi.nlm.nih.gov/articles/PMC11065979/
  160. https://ammo.com/research/stray-bullet-death-statistics
  161. https://www.policemag.com/articles/stopping-power-myths-legends-and-realities
  162. https://www.guns.com/news/hollow-point-ammunition-myths-and-misinformation
  163. https://www.police1.com/police-products/firearms/articles/why-overpenetration-is-nonsense-ssYXOnGCGDmHsxIO/
  164. https://www.thefirearmblog.com/blog/2016/04/19/top-4-ballistics-myths-people-believe/
  165. https://www.nationalreview.com/corner/abc-reports-urban-legend-as-news/
  166. https://www.researchgate.net/publication/2178262_Review_of_criticisms_of_ballistic_pressure_wave_experiments_the_Strasbourg_goat_tests_and_the_Marshall_and_Sanow_data
  167. https://www.mdshooters.com/threads/data-analysis-of-1800-shootings-by-caliber.269166/
  168. https://apps.dtic.mil/sti/tr/pdf/ADA519801.pdf
  169. https://www.globalsecurity.org/military/library/report/1986/MVT.htm
  170. https://www.pewresearch.org/short-reads/2025/03/05/what-the-data-says-about-gun-deaths-in-the-us/
  171. https://everytownresearch.org/graph/the-u-s-gun-homicide-rate-is-26-times-that-of-other-high-income-countries/
  172. https://everytownresearch.org/report/the-economic-cost-of-gun-violence/
  173. https://www.heritage.org/gun-rights/commentary/12-defensive-gun-uses-show-armed-citizens-make-communities-safer
  174. https://www.rand.org/research/gun-policy/analysis/defensive-gun-use.html
  175. https://www.hoplofobia.info/wp-content/uploads/2014/05/2020-CDC_Surveys_Prevalance_of_DGU.pdf
  176. https://academic.oup.com/book/4558/chapter/146650819
  177. https://www.rand.org/research/gun-policy/analysis/stand-your-ground.html
  178. http://international-review.icrc.org/articles/humanitarian-bullets-and-man-killers-920
  179. https://scholarlycommons.law.case.edu/cgi/viewcontent.cgi?article=1013&context=jil
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