A firearm is a tool that projects either single or multiple projectiles at high velocity through a controlled explosion. The firing is achieved by the gases produced through rapid, confined burning of a propellant. This process of rapid burning is technically known as deflagration. In older firearms, this propellant was typically black powder, but modern firearms use smokeless powder, cordite, or other propellants. Most modern firearms (with the notable exception of smoothbore shotguns) have rifled barrels to impart spin to the projectile for improved flight stability, increasing range and accuracy.
In the Middle Ages the term "firearm" was used in English to denote the arm in which the match was held that was used to light the touch hole on the hand cannon. The term was a variation on the contemporary terms of bow arm and drawing arm still used in archery. Due to the effects of firing the ordnance (barrel) at the time, the gunner had to be located somewhat behind the weapon, steadying brace with the other hand, hence the name "hand gun" became synonymous with the "fire arm." Although the modern term "gun" is often used as a synonym for firearm, in specialist or military use "gun" has a restricted sense referring only to an artillery piece with a relatively high muzzle velocity, such as a field gun, a tank gun, or a gun used in the delivery of naval gunfire. Artillery guns are much larger than these firearms, mounted on a movable carriage, having bores of up to 18 inches (46 cm) and possibly weighing many tons. Strictly speaking, such weapons are not firearms.
Hand-held firearms, like rifles, carbines, pistols, and other small firearms are rarely called "guns" in the restricted sense among specialists. Machine guns fire small caliber ammunition (generally 14.5 mm or smaller), and many machine guns are crew served infantry support weapons, requiring the services of more than one crewman, just like artillery guns. Generally, an automatic firearm designed for a single user is referred to as an automatic rifle. Other terms, including "firearm" itself, have been defined in specialized ad hoc ways by various legislation.
In recent centuries, firearms have become the predominant weapons used by humankind. Modern warfare since the late Renaissance has relied upon firearms, with wide-ranging effects on military history and history in general. This created a whole new kind of battle, which molded modern-era armies.
For handguns and long guns, the projectile is a bullet, or in historical hand cannons, a shot. The shot was initially made from lead already used as ammunition for the slings, and ironically begun with ballistic shape of a modern bullet, but was rapidly replaced by the cast iron ball. The projectile is fired by the burning of the propellant, but in small arms rarely contains explosives itself as such ammunition is banned by the Hague Convention. The use of expanding (for example, hollow-point) small-arms ammunition in warfare is also banned by the Convention for similar reason (it aggravates the severity of wounds from small-arms fire). For modern artillery the projectile is a shell, which almost always contains explosives, and explosives were also common in older artillery pieces as well.
Until the mid-1800s, projectiles and propellant (black powder) were generally separate components used in a muzzle-loading firearm such as a rifle, pistol, or cannon. Sometimes for convenience a suitable amount of powder and a bullet were wrapped in a paper package, known as a cartridge. This evolved into the form of a tubular metal casing enclosing a primary igniter (primer) and the powder charge, with the projectile press-fit into the end of the casing opposite the primer. Cartridge ammunition was widely adopted, and as of World War I it had become the primary form of ammunition for small arms, tanks, and artillery. Mortars use a similar concept of encapsulation; however, the projectile and casing are generally a single piece that is launched from the firearm. Some short-range naval guns use cased ammunition, but many battleship and cruiser main guns use a shell and separate bagged powder measures, which are selected according to the desired ballistic path.
A distinction is sometimes made between the projectile itself as the weapon and the firearm as a weapons platform. In some cases, the firearm can be used directly as a weapon without firing a projectile, although this is virtually always a secondary method of attack used in close combat. For example, arms such as rifles, muskets, and occasionally submachine guns can have bayonets affixed to them, becoming in effect a spear or pike. With some notable exceptions, the stock of a long gun can be used as a club. It is also possible to strike someone with the barrel of a firearm or grasp it by the barrel or grip and strike someone with the butt, which is informally called "pistol-whipping."
A problem for firearms is the accumulation of waste products from the partial combustion of propellants, metallic residue from the bullet itself, and small flecks of the cartridge case, known as fouling or gunshot residue. These waste products can interfere with the internal functions of the firearm. As a result, regularly used firearms must be periodically partially disassembled, cleaned and lubricated to ensure the firearm's reliability.
Firearms may sometimes be referred to as small arms. Small arms are firearms which can be carried by a single individual. According to international conventions governing the Laws of War, small arms are defined (with some exceptions) as firearms which fire a projectile not in excess of 15 mm (0.60 inches) in diameter. Small arms are aimed visually at their targets by hand using optical sights. The range of accuracy for small arms is generally limited to about one mile (1600 m), usually considerably less, although the current record for a successful sniper attack is slightly more than 1.5 miles (2.4 km).
The direct ancestor of the firearm is the fire-lance, a gunpowder-filled tube attached to the end of a spear and used as a flamethrower; shrapnel was sometimes placed in the barrel so that it would fly out together with the flames.12 The fire-lance had developed into the gun by the 1100s, the date of the earliest known depiction of a gun, a sculpture from a cave in Sichuan.1 The earliest Islamic documentation of the gun is from the work of the 13th century scientist Hasan al-Rammah. The earliest European documentation of the gun is Walter de Milemete's De Nobilitatibus, Sapientiis, et Prudentiis Regum from 1326. Gunpowder arrived in India by the mid-1300s, but could have been introduced by the Mongols perhaps as early as the mid-1200s.34
The Arabic engineer and chemist Hasan al-Rammah, in The Book of Military Horsemanship and Ingenious War Devices, described the earliest known recipes for an explosive gunpowder effect, some of which were almost identical to the ideal composition for explosive gunpowder used in modern times (75 percent saltpetre (KNO3), 10 percent sulfur, 15 percent carbon), such as the tayyar "rocket" (75 parts saltpetre, 8 sulfur, and 15 carbon, by weight) and the tayyar buruq "lightning rocket" (74 parts saltpetre, 10 sulfur, 15 carbon). He states in his book that many of these recipes were known to his father and grandfather, hence dating back to at least the late twelfth century. The earliest known military applications of these explosive gunpowder compositions were the explosive hand cannons first used by the Egyptians to repel the Mongols at the Battle of Ain Jalut in 1260.56
By the thirteenth century, explosive projectiles were being used by the Mongols in their invasions of Japan. A set of scrolls commissioned by Takezaki Suenaga, a Japanese warrior who fought against the Mongols, depict the Mongol's use of an exploding shell, known as a teppo. In addition, several more explosive shells have been discovered off the coast of Japan where several ships of the Mongol fleet sank during their second invasion.7
While firearms were beginning to form throughout Southeast Asia, the spread of gunpowder and its uses in weaponry also came to Portugal and Morocco.8 Gunpowder use in artillery had spread as far as Europe by 1500. Cannons as well as small firearms were being used by this time, and as a result warfare changed dramatically during this period. Gunpowder weapons now had widespread use in battle from this point on.
The smallest of all small arms is the handgun (or pistol). There are three common types of handguns: single-shot pistols (more common historically), revolvers, and semi-automatic pistols. Revolvers have a number of firing chambers or "charge holes" in a revolving cylinder; each chamber in the cylinder is loaded with a single cartridge. Semi-automatic pistols have a single fixed firing chamber machined into the rear of the barrel, and a removable magazine so they can be used to fire more than one round. The Italian-made Mateba revolver is a rare "hybrid," a semi-automatic revolver. Each press of the trigger fires a cartridge and rotates the cylinder so that the next cartridge may be fired immediately. The British firearms firm Webley also made an "automatic revolver" around the turn of the twentieth century.
Handguns differ from rifles and shotguns in that they are smaller, lack a shoulder stock (though some pistols like the Luger and Browning Hi-Power accept a removable stock allowing its use as a carbine), are usually chambered for less-powerful cartridges, and are designed to be fired with one or two hands. While the term "pistol" can be properly used to describe any handgun, it is common to refer to a single-shot or auto-loading handgun as a "pistol" and a revolver as a "revolver."A Glock 17 semi-automatic pistol
The term "automatic pistol" is sometimes used and is somewhat misleading in that the term "automatic" does not refer to the firing mechanism, but rather the reloading mechanism. When fired, an automatic pistol uses recoil and/or propellant gases to automatically extract the spent cartridge and insert a fresh one from a magazine. Usually (but not always) the firing mechanism is automatically cocked as well. An automatic pistol fires one shot per trigger pull, unlike an automatic firearm such as a machine gun, which fires as long as the trigger is held down and there are unspent cartridges in the chamber or magazine. There are, however, some fully automatic handguns (often referred to as machine pistols) so, to avoid such ambiguity and confusion, either "semi-automatic" or "autoloader" is preferred when referring to a firearm that fires only one shot per trigger pull.
Prior to the nineteenth century, all handguns were single-shot muzzleloaders. With the invention of the revolver in 1818, handguns capable of holding multiple rounds became popular. Certain designs of auto-loading pistol appeared beginning in the 1870s and had largely supplanted revolvers in military applications by the end of World War I. By the end of the twentieth century, most handguns carried regularly by military, police and civilians were semi-automatic, although revolvers were still widely used. Generally speaking, military and police forces use semi-automatic pistols due to their high magazine capacities (10 to 17 or, in some cases, over 25 rounds of ammunition) and ability to rapidly reload by simply removing the empty magazine and inserting a loaded one. Revolvers are very common among handgun hunters because revolver cartridges are usually more powerful than similar caliber semi-automatic pistol cartridges (which are designed for self-defense) and the strength, simplicity and durability of the revolver design is well-suited to outdoor use. Both designs are common among civilian gun owners, depending on the owner's intention (self-defense, hunting, target shooting, competitions, collecting, and so on).A Colt Single Action Army single-action revolver.
Handguns come in many shapes and sizes. For example, the "derringer" (a generic term based on the mid-nineteenth century "Deringer" brand name) is a very small, short-barreled handgun, usually with one or two barrels but sometimes more (some nineteenth century derringers had four barrels) that have to be manually reloaded after being fired. Carefully matched single-shot dueling pistols were used primarily in the eighteenth and nineteenth centuries to settle serious differences among "gentlemen:" Alexander Hamilton and Aaron Burr are probably the most prominent Americans who used dueling pistols to settle their differences. Revolvers and auto-loading pistols are produced in a wide variety of sizes, with autoloaders generally categorized as one of four sizes: Full-size, compact, sub-compact and ultra-compact. Each size has merits and shortcomings; a smaller handgun usually sacrifices ammunition capacity, recoil damping and/or long-range accuracy for increased concealability and ease of use by smaller-framed shooters. Fully automatic, relatively easily concealed machine pistols, such as the MAC-10, Glock 18, and the Beretta 93R, were a late twentieth century development.
Handguns are small and usually made to be carried in a holster, thus leaving both hands free. Small handguns can be easily concealed, thus making them a very common choice for personal protection. In the military, handguns are usually issued to those who are not expected to need more potent firearms, such as general and staff officers, and to those for whom there is no room for a full-sized rifle, such as vehicle crews. In this last role, they often compete with the carbine, a short, light rifle, which is also usually issued to airborne infantry because of its small size. Handguns were historically issued to riflemen as a secondary weapon, however the reliability and firepower of the modern assault rifle (and the increasing amount and cost of equipment carried by a soldier) has made this practice less common as of the end of the twentieth century. Outside the military, handguns are the usual armament for police and, where legal, for private citizens.
Private citizens in most jurisdictions usually carry only concealed handguns in public except when hunting, since an unconcealed firearm could attract undue attention, and could therefore be less secure, although 43 states in the U.S. permit open carry of handguns, sometimes subject to licensing or restrictions. In the United States, the number of states which permit concealed carry has recently grown to over 35, and several states have well over 200,000 permit holders. Despite Second Amendment constitutional roots in the United States, the concept of citizens carrying a concealed firearm for self-defense is often a contentious political issue; see gun politics for more information.
Handguns are also used for many sporting purposes and hunting, although hunting usage is usually viewed as somewhat atypical due to the limited range and accuracy of handguns. Some hunters, however, do their hunting in areas of dense cover where long guns would be awkward, or they relish the increased challenge involved in handgun hunting due to the necessity of approaching the game animal more closely. Handgun ammunition is also generally less expensive than rifle cartridges, and is usually sufficient for many larger pest animals such as feral hogs, coyotes, and wolves. Small-bore (for example, .22 caliber rimfire) handguns have long been very popular for competitive target shooting, partially due to the low cost of both the firearms and the ammunition, and there is also a rapidly growing number of sporting competitions for larger calibers, including "practical shooting," the guidelines of which usually require a handgun of caliber 9x19 mm or greater.
Long gunsSpringfield Armory M1903 rifle.
Most modern long guns are either rifles or shotguns. Historically, a long smoothbore firearm was known as a musket. A rifle has a rifled barrel that fires single bullets, while a shotgun fires packets of shot, a single slug, a sabot, or a specialty round (such as tear gas, bolo shell, or a breaching round). Rifles have a very small impact area but a long range and high accuracy. Shotguns have a large impact area with considerably less range and accuracy. However, the larger impact area can compensate for reduced accuracy, since shot spreads during flight; consequently, in hunting, shotguns are used for flying game.
Rifles and shotguns are commonly used for hunting and often to defend a home or place of business. Usually, large game are hunted with rifles (although shotguns can be used), while birds are hunted with shotguns. Shotguns are sometimes preferred for defending a home or business due to their wide impact area, multiple wound tracks (when using buckshot), shorter range, and reduced penetration of walls, which significantly reduces the likelihood of unintended harm, although the handgun is also common.
There are a variety of types of rifles and shotguns based on the method they are reloaded. Bolt-action and lever-action rifles are manually operated. Manipulation of the bolt or the lever causes the spent cartridge to be removed, the firing mechanism recocked, and a fresh cartridge inserted. These two types of action are almost exclusively used by rifles. Slide-action (commonly called "pump-action") rifles and shotguns are manually cycled by shuttling the foregrip of the firearm back and forth. This type of action is typically used by shotguns, but several major manufacturers make rifles that use this action.
Both rifles and shotguns also come in break-action varieties that do not have any kind of reloading mechanism at all but must be hand-loaded after each shot. Both rifles and shotguns come in single- and double-barreled varieties; however due to the expense and difficulty of manufacturing, double-barreled rifles are rare. Double-barreled rifles are typically intended for African big-game hunts where the animals are dangerous, ranges are short, and speed is of the essence. Very large and powerful calibers are normal for these firearms.
Rifles have been in nationally featured marksmanship events in Europe and the United States since at least the eighteenth century, when rifles were first becoming widely available. One of the earliest purely "American" rifle-shooting competitions took place in 1775, when Daniel Morgan was recruiting sharpshooters in Virginia for the impending American War of Independence. In some countries, rifle marksmanship is still a matter of national pride. Some specialized rifles in the larger calibers are claimed to have an accurate range of up to about one mile (1600 m), although most have considerably less. In the second half of the twentieth century, competitive shotgun sports became perhaps even more popular than riflery, largely due to the motion and immediate feedback in activities such as skeet, trap, and sporting clays.
In military use, bolt-action rifles with high-power scopes are common as sniper rifles, however by the Korean War the traditional bolt-action and semi-automatic rifles used by infantrymen had been supplanted by select-fire designs known as "automatic rifles" (see "Automatic Rifle" in the next section)
An automatic weapon is a firearm capable of firing multiple rounds with one pull of the trigger. The Gatling gun was an early crank-operated weapon that may have been the first automatic weapon, though the modern trigger-actuated machine gun was not widely introduced until the First World War with the German "Spandau" and British Lewis gun. Automatic weapons are largely restricted to military and paramilitary organizations, though many automatic designs are infamous for their use by organized crime.
Automatic firearms have long been available to U.S. civilians, under increasingly restrictive conditions. Importation of machine guns for civilian sale in the U.S. was banned by the Gun Control Act of 1968. The Hughes Amendment to the Firearm Owners Protection Act now prohibits U.S. civilian ownership or transfer of automatic weapons unless they were registered before May 19, 1986. Non-prohibited automatic weapons can be legally transferred to civilians who pay a substantial tax to the BATFE and pass a background investigation, although permission must be received from BATFE to move a machine gun between states. An extremely limited number of U.S. citizens have special permits from the BATFE to buy, and even import, automatic weapons produced and registered after 1986. The use of such weapons is tightly restricted to the film industry under direct supervision of the master of arms holding the permit, and the weapons are often altered so they will not fire "factory" ammunition, but rather only special "light-primer" blank cartridges produced specifically for the film industry. This arrangement allows weapons first produced after 1986 to be used by actors in films and TV series filmed inside the U.S.
A machine gun is a fully automatic emplaceable weapon, generally separated from other classes of automatic weapon by the use of belt-fed ammunition (though some designs employ drum, pan or hopper magazines), generally in a rifle-inspired caliber ranging between 5.56mm NATO to as large as .50 BMG or larger for crewed or aircraft weapons. Although not widely fielded until World War I, early machine guns were being used by the military in the second half of the 19th century. They were primarily defensive firearms crewed by two men, mainly because of the difficulties involved in moving and placing them, and their inherent lack of accuracy. In contrast, modern light machine guns such as the FN Minimi are often wielded by a single infantryman. They provide a large ammunition capacity and a high rate of fire and are typically used to give suppressing fire during infantry movement. Machine guns are also often mounted on vehicles or helicopters, and have often been used since World War I as offensive firearms in fighter aircraft and tanks (for example, for air combat or suppressing fire for ground troop support).
The definition of machine gun is different in U.S. law. The National Firearms Act and Firearm Owners Protection Act define a "machine gun" in the United States code Title 26, Subtitle E, Chapter 53, Subchapter B, Part 1, § 5845 as: "… any firearm which shoots… automatically more than one shot, without manual reloading, by a single function of the trigger." "Machine gun" is therefore largely synonymous with "automatic weapon" in the US civilian parlance, covering all automatic firearms.
A submachine gun is a magazine-fed firearm, usually smaller than other automatic firearms, that fires pistol-caliber ammunition; for this reason submachine guns are also commonly called machine pistols especially when referring to handgun-sized designs such as the Škorpion vz. 61 and Glock 18. Well-known examples are the Israeli Uzi, the 9x19mm Parabellum cartridge, the American Thompson submachine gun which fires .45 ACP, and the Belgian FN P90 which uses a new 5.7x28 mm cartridge. Because of their small size and limited projectile penetration compared to high-power rifle rounds, submachine guns are commonly favored by military, paramilitary, and police forces for close-quarters engagements such as inside buildings, in urban areas or in trench complexes.
A related class of firearm is the "Personal Defense Weapon" or PDW, which is in simplest terms a submachine gun designed to fire rounds similar to rifle cartridges. A submachine gun is desirable for its compact size and ammunition capacity, however a pistol round lacks the penetrating capability of a rifle round. Conversely, rifle bullets can pierce light armor and are easier to shoot accurately, but even a carbine is larger or longer than a submachine gun, making it harder to maneuver in close quarters. The solution many firearms manufacturers have presented is a weapon resembling a submachine gun in size and general configuration, but which fires a higher-powered armor-penetrating round, thus combining the advantages of a carbine and submachine gun. The FN P90 and H&K MP7 are examples.
Automatic rifleA U.S. Marine training with an AK-47 assault rifle
An automatic rifle is a magazine-fed long gun, wielded by a single infantryman, that is chambered for rifle cartridges and capable of automatic fire. The Browning Automatic Rifle was the first U.S. infantry weapon of this type, and was generally used for suppressive or support fire in the role now usually filled by the light machine gun. Other early automatic rifles include the Federov Avtomat and the Huot automatic rifle. Later, the German forces fielded the Sturmgewehr 44 during World War II, a light automatic rifle firing a reduced power "intermediate cartridge." This design was to become the model for the "assault rifle" subclass of automatic weapons. After World War II, the M14 (a gas-actuated select-fire design that replaced the M1 Garand) was introduced in the U.S., followed by the M16A1 assault rifle which was widely used in the Vietnam War. Also soon after World War II, the Automat Kalashnikov AK-47 assault rifle was fielded by the Soviet Union and other Communist allies including the Eastern Bloc, China, North Korea, and North Vietnam. Variants of both of the M16 and AK-47 are still in wide international use today, though other automatic rifle designs have since been introduced. A smaller version of the M16A2, the M4 carbine, is widely used by tank and vehicle crews, airbornes, support staff, and in other scenarios where space is limited. The IMI Galil, an Israeli-designed weapon similar to the AK-47, is in use by Israel, Italy, Myanmar, the Philippines, Peru, and Colombia. Swiss Arms AG of Switzerland produces the Sig 550 assault rifle used by France, Chile, and Spain among others, and Steyr Mannlicher produces the AUG, a bullpup rifle in use in Austria, Australia, New Zealand, Ireland and Saudi Arabia among other nations.
Loading and firing mechanisms
Muzzle-loaded hand cannonHand cannon being fired from a stand, "Belli Fortis," manuscript, by Konrad Kyeser, 1400
The original predecessor of all firearms, the hand cannon was loaded with gunpowder and the shot (initially lead shot, later replaced by cast iron) through the muzzle, while a fuse was placed at the rear. This fuse was lighted, causing the gunpowder to ignite and propel the cannonball. In military use, the standard hand cannon was tremendously powerful, while also being somewhat useless due to relative inability of the gunner to aim the weapon, or control the ballistic properties of the projectile. Recoil, a principle new to human experience at the time, could only be absorbed by bracing the barrel against the ground using a wooden support, the forerunner of the stock. Neither the amount of gunpowder, nor the consistency in projectile dimensions were controlled, with resulting inaccuracy in firing due to windage, the difference in diameter between the bore and the shot. The hand cannons were replaced by lighter carriage-mounted artillery pieces, and ultimately the arquebus.
Muzzle-loading muskets (smooth-bored long guns) were among the first small arms developed. The firearm was loaded through the muzzle with gunpowder, optionally some wadding and then a bullet (usually a solid lead ball, but musketeers could shoot stones when they ran out of bullets). Greatly improved muzzleloaders (usually rifled instead of smooth-bored) are manufactured today and have many enthusiasts, many of whom hunt large and small game with their guns. Muzzleloaders have to be manually reloaded after each shot; a skilled archer could fire multiple arrows faster than most early muskets could be reloaded and fired, although by the mid-18th century, when muzzleloaders became the standard small armament of the military, a well-drilled soldier could fire six rounds in a minute using prepared cartridges in his musket. Before then, effectiveness of muzzleloaders was hindered by both the low reloading speed and, before the firing mechanism was perfected, the very high risk posed by the firearm to the person attempting to fire it.
One interesting solution to the reloading problem was the "Roman Candle Gun." This was a muzzleloader in which multiple charges and balls were loaded one on top of the other, with a small hole in each ball to allow the subsequent charge to be ignited after the one ahead of it was ignited. It was neither a very reliable nor popular firearm, but it enabled a form of "automatic" fire long before the advent of the machine gun.9
Matchlocks were the first and simplest small arms firing mechanisms developed. Using the matchlock mechanism, the powder in the gun barrel was ignited by a piece of burning cord called a "match." The match was wedged into one end of an S-shaped piece of steel. As the trigger (often actually a lever) was pulled, the match was brought into the open end of a "touch hole" at the base of the gun barrel, which contained a very small quantity of gunpowder, igniting the main charge of gunpowder in the gun barrel. The match usually had to be relit after each firing.
The wheellock action, a successor to the matchlock, predated the flintlock. Despite its many faults, the wheellock was a significant improvement over the matchlock in terms of both convenience and safety, since it eliminated the need to keep a smoldering match in proximity to loose gunpowder. It operated using a small wheel much like that on cigarette lighters which was wound up with a key before use and which, when the trigger was pulled, spun against a flint, creating the shower of sparks that ignited the powder in the touch hole. Supposedly invented by Leonardo da Vinci, the Italian Renaissance man, the wheel lock action was an innovation that was not widely adopted.
The flintlock action was a major innovation in small arms design. The spark used to ignite the gunpowder in the touch hole was supplied by a sharpened piece of flint clamped in the jaws of a "cock" which, when released by the trigger, struck a piece of steel called the "frizzen" to create the necessary sparks. (The spring loaded arm that holds a piece of flint or pyrite is referred to as a cock because of its resemblance to a rooster.) The cock had to be manually reset after each firing, and the flint had to be replaced periodically due to wear from striking the frizzen. (See also flintlock mechanism, snaphance, miquelet) The flintlock was widely used during the 18th and 19th centuries in both muskets and rifles.
Percussion caps (caplock mechanisms), coming into wide service in the nineteenth century, were a dramatic improvement over flintlocks. With the percussion cap mechanism, the small primer charge of gunpowder used in all preceding small arms was replaced by a completely self-contained explosive charge contained in a small brass "cap." The cap was fastened to the touch hole of the gun (extended to form a "nipple") and ignited by the impact of the gun's "hammer." (The hammer is roughly the same as the cock found on flintlocks except that it doesn't clamp onto anythin