Firearm
A firearm is a kinetic energy mechanical device that fires either single or multiple projectiles propelled at high velocity by the gases produced by action of the 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 or other propellants.
The term gun is often used as a synonym for firearm, but in specialist use has a restricted sense—referring only to an artillery piece with a relatively high muzzle velocity and a relatively flat trajectory, such as a field gun, a [[tank gun], an anti-tank gun, or a naval gun. Guns are distinct from howitzers and mortars, which have lower muzzle velocities and higher trajectories. Hand-held firearms, like rifles, carbines, pistols and other small firearms are never called "guns" in the restricted sense.
In recent centuries, firearms have become the predominant weapons used by mankind. Modern warfare since the late Renaissance has relied upon firearms, with wide-ranging effects on military history and history in general.
For handguns and long guns, the projectile is a bullet or, in historical cannons, a cannonball. The projectile is fired by the burning of the propellant, but in small arms rarely contains explosives itself. For modern artillery the projectile is a shell, which nearly always contains explosives.
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 generally a secondary method of attack. 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 handgun or grasp it by the barrel and strike someone with the butt. This is 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. 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 weapon's reliability.
There are two basic categories of firearms: artillery pieces and small arms. Small arms are generally small, very portable firearms with a barrel bore of up to approximately 0.50 inch (12.7 mm)and are aimed visually at their targets using sights. The range of accuracy for small arms is limited to about one mile (1600 m), usually considerably less. Artillery pieces are much larger, mounted on a movable carriage, having bores of up to 18 inches (46 cm) and possibly weighing many tons. Artillery can be accurate at ranges of up to about 26 miles (42 km) and, with some notable exceptions (e.g., tank guns), is aimed using altitude/azimuth settings. Strictly speaking, not all small arms are firearms, but it is the most convenient category under which to group them.
Small arms
Handguns
The smallest of all small arms is the handgun (or "sidearm"). Handguns with a single, fixed firing chamber are pistols; most pistols have a removable magazine so they can be used to fire several shots. The other most common handgun design is the revolver, which has a number of firing chambers in a revolving cylinder; each chamber in the cylinder is loaded with a single cartridge.
Prior to the 19th century, all handguns were single-shot muzzleloaders. With the invention of the revolver in 1818, handguns capable of holding multiple rounds became popular. At the end of the 20th century, most handguns are semiautomatic, although revolvers are still widely used.
Handguns come in many shapes and sizes. For example, the "derringer" (a generic term based on the mid-19th-century "Derringer" brand name) is a very small, short-barreled handgun, usually with one or two barrels but sometimes more (some 19th-century derringers had four barrels) that have to be manually reloaded after being fired. Carefully matched single-shot duelling pistols were used primarily in the 18th and 19th centuries to settle serious differences among "gentlemen": Alexander Hamilton and Aaron Burr are probably the most prominent Americans who used duelling pistols to settle their differences. Fully automatic, easily concealed machine pistols, such as the MAC-10 and the H&K MP5, were a late 20th-century development.
Handguns are small and usually made to be easily concealed, thus making them a very common choice for personal protection. In the military, handguns are usually issued to those who do not need larger firearms, such as general and staff officers, and to those for whom there is no room for a full-sized rifle, such as armored vehicle and air crews. In this last role, they often compete with the carbine, which is also usually issued to airborne infantry because of its small size. Outside the military, handguns are the usual armament for police (in those jurisdictions where police are armed) and, where legal, for private citizens. Private citizens usually carry only concealed handguns in public, since an unconcealed weapon would attract undue attention, and would therefore be less secure. In the United States, the number of states which permit concealed carry has recently grown to over 35, and several states have well over 100,000 permit holders. Despite constitutional roots in the United States, the concept of citizens carrying a concealed weapon for self-defense has become 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. In particular, small-bore (e.g., .22 caliber) handguns have long been very popular for competitive target shooting, and there is a rapidly growing number of sporting competitions for larger calibers. In general, handguns are not considered to be accurate at distances greater than about 50 yards.
Long guns
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 (tear gas, bolo, lead powder, etc.). Rifles are often built for accuracy and long range and are aimed, while shotguns are usually designed to quickly hit a moving target and are instead "pointed". 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—deer hunting with a shotgun is possible with the use of buckshot, sabots or slugs) while birds are hunted with shotguns. Shotguns are sometimes preferred for defending a home or business due to their wide impact area, shorter range, and reduced penetration of walls, which significantly reduces the likelihood of unintended harm, although the handgun is also commonly preferred.
Rifles have been in nationally featured marksmanship events in Europe and the United States since at least the 18th 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 war with England. 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, although most have considerably less range. In the second half of the 20th 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.
Machine guns
A machine gun is a fully automatic firearm used almost exclusively by the military. Although not widely fielded until World War I, early machine guns were being used by the military in the late 19th century (e.g., the Gatling gun). They are primarily defensive weapons, mainly because of the difficulties involved in moving and placing them, and their inherent lack of accuracy. In contrast, light machine guns (such as the U.S. military's M249 Squad Automatic Weapon and the M60, both of which are small-caliber weapons) are often wielded by a single infantryman; they provide a high rate of fire typically used as either suppressing fire or covering fire during infantry movement. Machine guns are also often mounted on vehicles or helicopters, and have often been used since World War II as offensive weapons in fighter aircraft and tanks (e.g., for air combat or suppressing fire for ground troop support).
A submachine gun is a machine gun that fires cartridges that would otherwise be used in a handgun. Probably the most well-known example of a submachine gun is the Thompson gun (the "Tommy Gun" of gangster movies), which fires .45 ACP cartridges.
In United States law, a Machine Gun is defined (in part) by The National Firearms Act of 1934, United States code Title 26, Subtitle E, Chapter 53, Subchapter B, Part 1, § 5845 as:
"... any weapon which shoots ... automatically more than one shot, without manual reloading, by a single function of the trigger."
In the United States, purchases of machine guns manufactured after 1986 by civilians were banned by the Firearm Owners Protection Act (FOPA), passed in that year. Importation of machine guns for civilian sale in the U.S. was banned by the Gun Control Act of 1968. Machine guns manufactured prior to 1986 or imported prior to 1968 can still be legally transferred to civilians who pay a substantial tax to the BATFE and pass a background investigation. In addition, "transferable" machine guns must have been registered with the BATFE prior to 1986. Machine Gun parts kits (which do not include a functional receiver) can be transferred without restriction. Permission must be received from BATFE to move a machine gun between states.
Loading and firing mechanisms
Cannon
The cannon is loaded with gunpowder and the cannonball through the muzzle, while a fuse is placed at the rear. This fuse is lighted, causing the gunpowder to ignite and propel the cannonball. Most cannons were land- or ship-based guns, although hand cannons also existed. In military use, the standard cannon was tremendously powerful, while hand cannon was somewhat useless. In the 19th century, the muzzle-loaded cannon was made obsolete by the breech-loaded artillery piece with a rifled barrel.
Muzzleloader
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 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 weapon 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 enable a form of "automatic" fire long before the advent of the machine gun.
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Matchlock
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.
Wheellock
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 close 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.
Flintlock
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 "hammer" which, when released by the trigger, struck a piece of steel called the "frizzen" to create the necessary sparks. The hammer 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 cap
Percussion caps (caplock mechanisms), coming into wide service in the 19th 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 flame from the cap in turn ignited the main charge of gunpowder, as with the flintlock, but there was no longer any need to charge the touch hole with gunpowder, and even better, the touch hole was no longer exposed to the elements. As a result, the percussion cap mechanism was considerably safer, far more weatherproof, and vastly more reliable (cloth-bound cartridges containing a premeasured charge of gunpowder and a ball had been in regular military service for many years, but the exposed gunpowder in the entry to the touch hole had long been a source of misfires). All muzzleloaders manufactured since the second half of the 19th century use percussion caps except those built as replicas of the flintlock or earlier small arms.
Cartridges
A major innovation in small arms (and light artillery) came in the second half of the 19th century when ammunition, previously delivered as separate bullets and powder, was combined in a single metallic (almost always brass) cartridge containing a percussion cap, powder, and a bullet in one weatherproof package. Before this, a "cartridge" was simply a premeasured quantity of gunpowder together with a ball in a small cloth bag, which also acted as wadding for the charge and ball. This early form of cartridge had to be rammed into the muzzleloader's barrel, and either a small charge of gunpowder in the touch hole or an external percussion cap mounted on the touch hole ignited the gunpowder in the cartridge. Cartridges with built-in percussion caps (called "primers") continue to this day to be the standard in firearms. In cartridge-firing firearms, a hammer (or a firing pin struck by the hammer) strikes the cartridge primer, which then ignites the gunpowder within. The primer charge is at the base of the cartridge, either within the rim (a "rimfire" cartridge) or in a small percussion cap embedded in the center of the base (a "centerfire" cartridge). As a rule, centerfire cartridges are more powerful than rimfire cartridges, containing more gunpowder and (usually) larger diameter bullets.
Caseless cartridges are now being explored: instead of using brass as the cartridge case, these would hold the cartridge together with paper or some other substance that is destroyed when the gun is fired, eliminating the problem of brass casings ejecting and littering the ground. Caseless cartridges and the guns that would use them are still prototypes, although the idea of caseless cartridges can be traced to the musket "cartridges" widely used by the 18th-century military.
Nearly all contemporary firearms load cartridges directly into their breech. Some additionally or exclusively load from a magazine that holds multiple cartridges. A magazine is a box or cylinder that is designed to be reusable and is detachable from the gun. Some magazines, such as those of the Garand are loaded by using a clip, which is a device that looks like a rail holding the ammunition by the case base. In most cases, a magazine and a clip are different in that the former's function is to feed ammunition into the firearm's breech, while the latter's is only to "charge" a magazine with fresh ammunition.
Repeating, semiautomatic, and automatic weapons
Many small arms are "single shot" firearms: i.e., each time a cartridge is fired, the operator must manually recock the firearm and load another cartridge. A firearm that can load multiple cartridges as the weapon is recocked is considered a repeating weapon or simply a "repeater". A firearm that automatically recocks and reloads the next round with each trigger pull is considered a semiautomatic weapon. An automatic (or "fully automatic") weapon is one that automatically recocks, reloads, and refires as long as the trigger is depressed. Many modern military firearms have a "selective-fire" option, which is a mechanical switch that allows the weapon be fired either in the semiautomatic or fully automatic mode. In the current M16A2 and M16A4 variants of the U.S.-made M16, continuous full-automatic fire is not possible, having been replaced by an automatic burst of three cartridges that makes full-automatic fire considerably more accurate. It is sometimes debated which is the "best" military small arm, the former Soviet Union's 7.62x39mm- Kalishnikov AK-47 or the U.S.-manufactured .223-caliber M16: the highly reliable and inexpensive but heavy and bulky AK-47 has been widely adopted by many small countries, including many current and former Communist nations. The much lighter and far more accurate M16 (and its .223 cartridge in particular) has found wide adoption among NATO members and military allies of the United States (see also AK-47 vs. M16).
The first "rapid firing" weapons were usually similar to the 19th-century Gatling gun, which would fire cartridges from a magazine as fast as and as long as the operator turned a crank. Eventually, the "rapid" firing mechanism was perfected and miniaturized to the extent that either the recoil of the firearm or the gas pressure from firing could be used to operate it (which made the firing mechanisms truly "automatic"). Automatic rifles such as the Browning Automatic Rifle (the "BAR") were in common use by the military during the early part of the 20th century, and automatic rifles that fired handgun rounds, known as submachine guns, also appeared in this time.
Submachine guns (such as the well-known Thompson gun) were originally about the size of carbines. In the latter half of the 20th century, submachine guns were being miniaturized to the point of being only slightly larger than some (albeit large) handguns. The most widely used submachine gun at the end of the 20th century was the Heckler & Koch MP5. The MP5 is actually designated as a "machine pistol" by Heckler & Koch (MP5 stands for Machine Pistol 5), although some reserve this designation for even smaller submachine guns such as the MAC-10, which are about the size and shape of pistols.
Nazi Germany brought the world's attention to what eventually became the class of weapon most widely adopted by the military: the so-called assault rifle. An assault rifle is usually slightly smaller than a military rifle such as the M1 Garand but has selective fire (civilian "assault rifle" look-alikes are strictly semiautomatic). Soviet engineer Mikhail Kalashnikov quickly adapted the concept to the AK-47, which has become the world's most widely used assault rifle. In United States, John Garand, the inventor of the M1 Garand rifle used by the U.S. military during World War II, adapted the assault rifle design to produce the M14, which was used by the U.S. military until the 1960s. The significant recoil (hence inaccuracy) of the M14 when fired in full automatic mode was seen as a problem, however, and in the 1960s it was replaced by Eugene Stoner's AR-15, which also marked a switch from the high-powered but heavy .30-caliber rifle used by the U.S. military since World War I to the much smaller but far lighter and light recoiling (more accurate) .223-caliber rifle. The military later redesignated the AR-15 as the "M16". The civilian version of the M16 continues to be known as the AR-15 and looks exactly like the military version, although it is strictly a semiautomatic firearm.
See also
Related articles
Gun technology and science
- Ballistics
- Electrothermal-chemical technology
- Firearm action
- Optics
- Physics of firearms
- Silencer
- Terminal ballistics
- Cartridge (weaponry)
- Bullet
Guns and society
Gun law - Gun politics - Gun safety - Concealed carry - List of United States firearms topics
Lists of weapons
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WW II Era
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- List of World War II firearms
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- List of prototype World War II infantry weapons
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- List of individual weapons of the U.S. Armed Forces
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