A firearm is a portable gun (a barreled ranged
weapon) designed for use by a single individual. It inflicts damage on targets by launching
one or more projectiles driven by rapidly expanding high-pressure gas produced by exothermic
combustion (deflagration) of chemical propellant. If gas pressurization is achieved through
mechanical gas compression rather than through chemical propellant combustion, then the gun
is technically an air gun, not a firearm.The first primitive firearms originated in 10th-century
China when bamboo tubes containing gunpowder and pellet projectiles were mounted on spears
into the one-person-portable fire lance, which was later used as a shock weapon to good effect
in the Siege of De’an in 1132. In the 13th century the Chinese invented the metal-barrelled
hand cannon, widely considered the true ancestor of all firearms. The technology gradually
spread through the rest of East Asia, South Asia, the Middle East, and Europe. Older firearms
typically used black powder as a propellant, but modern firearms use smokeless powder 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.
Modern firearms can be described by their caliber (i.e. their bore diameter; this is
given in millimeters or inches e.g. 7.5 mm, .357 in.) or in the case of shotguns by their
gauge (e.g. 12 ga.); by the type of action employed (muzzleloader, breechloader, lever,
bolt, pump, revolver, semi-automatic, fully automatic, etc.) together with the usual means
of deportment (hand-held or mechanical mounting). Further classification may make reference
to the type of barrel used (rifled) and to the barrel length (24 inch), to the firing
mechanism (e.g. matchlock, wheellock, flintlock, percussion lock), to the design’s primary
intended use (e.g. hunting rifle), or to the commonly accepted name for a particular variation
(e.g. Gatling gun). Shooters aim firearms at their targets with
hand-eye coordination, using either iron sights or optical sights. The accurate range of pistols
generally does not exceed 110 yards (100 m), while most rifles are accurate to 550 yards
(500 m) using iron sights, or to longer ranges using optical sights (firearm rounds may be
dangerous or lethal well beyond their accurate range; the minimum distance for safety is
much greater than the specified range). Purpose-built sniper rifles and anti-materiel rifles are
accurate to ranges of more than 2,200 yards (2,000 m).==Types of firearms==
Firearms include a variety of ranged weapons and there is no agreed upon definition.
In the United States, Under 26 USCA § 861 (a), The term ‘‘firearm’’ means (1)
a shotgun having a barrel or barrels of less than 18 inches in length; (2) a weapon made
from a shotgun if such weapon as modified has an overall length of less than 26 inches
or a barrel or barrels of less than 18 inches in length; (3) a rifle having a barrel or
barrels of less than 16 inches in length; (4) a weapon made from a rifle if such weapon
as modified has an overall length of less than 26 inches or a barrel or barrel of less
than 16 inches in length; (5) any other weapon, as defined in subsection (e); (6) a machinegun;
(7) any silencer (as defined in section 921 of title 18, United States Code); The term
‘‘firearm’’ shall not include an antique firearm or any device (other than a machinegun
or destructive device) which, although designed as a weapon, the Secretary finds by reason
of the date of its manufacture, value, design, and other characteristics is primarily a collector’s
item and is not likely to be used as a weapon.===Configuration===The term “small arms” generally refers to
any kinetic projectile firearm small and light enough to be carried and operated by a single
infantryman. These include handguns such as revolvers, pistols and derringers, and long
guns such as rifles (of which there are many subtypes such as anti-material rifles, sniper
rifles, designated marksman rifles, battle rifles, assault rifles and carbines), shotguns,
submachine guns, personal defense weapons, squad automatic weapons and light machine
guns.The world’s top small arms manufacturing companies are Browning, Remington, Colt, Ruger,
Smith & Wesson, Savage, Mossberg (USA), Heckler & Koch, SIG Sauer, Walther (Germany), ČZUB
(Czech Republic), Glock, Steyr-Mannlicher (Austria), FN Herstal (Belgium), Beretta (Italy),
Norinco (China), Tula Arms and Kalashnikov (Russia), while former top producers were
Mauser, Springfield Armory, and Rock Island Armory under Armscor (Philippines).
In 2018, Small Arms Survey reported that there are over one billion small arms distributed
globally, of which 857 million (about 85 percent) are in civilian hands. U.S. civilians alone
account for 393 million (about 46 percent) of the worldwide total of civilian held firearms.
This amounts to “120.5 firearms for every 100 residents.” The world’s armed forces control
about 133 million (about 13 percent) of the global total of small arms, of which over
43 percent belong to two countries: the Russian Federation (30.3 million) and China (27.5
million). Law enforcement agencies control about 23 million (about 2 percent) of the
global total of small arms.====Handguns====The smallest of all firearms is the handgun.
There are two common types of handguns: 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 or charge. Semi-automatic pistols have a single
fixed firing chamber machined into the rear of the barrel, and a magazine so they can
be used to fire more than one round. Each press of the trigger fires a cartridge, using
the energy of the cartridge to activate the mechanism so that the next cartridge may be
fired immediately. This is opposed to “double-action” revolvers which accomplish the same end using
a mechanical action linked to the trigger pull.
Prior to the 19th century, virtually 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 20th
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 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. Revolvers, especially in .22 LR and 38 Special/357 Magnum, are also common concealed
weapons in jurisdictions allowing this practice because their simple mechanics make them smaller
than many autoloaders while remaining reliable. Both designs are common among civilian gun
owners, depending on the owner’s intention (self-defense, hunting, target shooting, competitions,
collecting, etc.).====Long guns====A long gun is generally any firearm that is
larger than a handgun and is designed to be held and fired with both hands, either from
the hip or the shoulder. Long guns typically have a barrel between 10 and 30 inches (there
are restrictions on minimum barrel length in many jurisdictions; maximum barrel length
is usually a matter of practicality), that along with the receiver and trigger group
is mounted into a wood, plastic, metal or composite stock, composed of one or more pieces
that form a foregrip, rear grip, and optionally (but typically) a shoulder mount called the
butt. Early long arms, from the Renaissance up to the mid-19th century, were generally
smoothbore firearms that fired one or more ball shot, called muskets or arquebus depending
on caliber and firing mechanism.=====Rifles and shotguns=====Most modern long guns are either rifles or
shotguns. Both are the successors of the musket, diverging from their parent weapon in distinct
ways. A rifle is so named for the spiral fluting (rifling) machined into the inner surface
of its barrel, which imparts a self-stabilizing spin to the single bullets it fires. Shotguns
are predominantly smoothbore firearms designed to fire a number of shot; pellet sizes commonly
ranging between 2 mm #9 birdshot and 8.4 mm #00 (double-aught) buckshot. Shotguns are
also capable of firing single slugs, or specialty (often “less lethal”) rounds such as bean
bags, tear gas or breaching rounds. 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 generally 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,
particularly with slugs), 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 (when using
lighter shot), 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 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 American Revolutionary War. 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 1 mile (1,600 m), although most have considerably
less. 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. 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 supplemented by select-fire designs
known as “automatic rifles”.=====Carbines=====A carbine is a firearm similar to a rifle
in form and intended usage, but generally shorter or smaller than the typical “full-size”
hunting or battle rifle of a similar time period, and sometimes using a smaller or less-powerful
cartridge. Carbines were and are typically used by members of the military in roles that
are expected to engage in combat, but where a full-size rifle would be an impediment to
the primary duties of that soldier (vehicle drivers, field commanders and support staff,
airborne troops, engineers, etc.). Carbines are also common in law enforcement and among
civilian owners where similar size, space and/or power concerns may exist. Carbines,
like rifles, can be single-shot, repeating-action, semi-automatic or select-fire/fully automatic,
generally depending on the time period and intended market. Common historical examples
include the Winchester Model 1892, Lee–Enfield “Jungle Carbine”, SKS, M1 carbine (no relation
to the larger M1 Garand) and M4 carbine (a more compact variant of the current M16 rifle).
Modern U.S. civilian carbines include compact customizations of the AR-15, Ruger Mini-14,
Beretta Cx4 Storm, Kel-Tec SUB-2000, bolt-action rifles generally falling under the specifications
of a scout rifle, and aftermarket conversion kits for popular pistols including the M1911
and Glock models.=====Machine guns=====A machine gun is a fully automatic emplaceable
weapon, most often separated from other classes of automatic weapons by the use of belt-fed
ammunition (though some designs employ drum, pan or hopper magazines), generally in a rifle-inspired
caliber ranging between 5.56×45mm NATO (.223 Remington) for a light machine gun to as large
as .50 BMG or even larger for crewed or aircraft weapons. Although not widely fielded until
World War I, early machine guns were being used by militaries in the second half of the
19th century. Notables in the U.S. arsenal during the 20th century included the M2 Browning
.50 caliber heavy machine gun, M1919 Browning .30 caliber medium machine gun, and the M60
7.62×51mm NATO general-purpose machine gun which came into use around the Vietnam War.
Machine guns of this type were originally defensive firearms crewed by at least two
men, mainly because of the difficulties involved in moving and placing them, their ammunition,
and their tripod. 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. Accuracy on
machine guns varies based on a wide number of factors from design to manufacturing tolerances,
most of which have been improved over time. Machine guns are often mounted on vehicles
or helicopters, and have been used since World War I as offensive firearms in fighter aircraft
and tanks (e.g. 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 U.S. civilian parlance, covering all automatic firearms.=====Sniper rifles=====The definition of a sniper rifle is disputed
among military, police and civilian observers alike, however most generally define a “sniper
rifle” as a high powered, semi-automatic/bolt action, precision rifle with an accurate range
further than that of a standard rifle. These are often purpose-built for their applications.
For example, a police sniper rifle may differ in specs from a military rifle. Police snipers
generally do not engage targets at extreme range, but rather, a target at medium range.
They may also have multiple targets within the shorter range, and thus a semi-automatic
model is preferred to a bolt action. They also may be more compact than milspec rifles
as police marksmen may need more portability. On the other hand, a military rifle is more
likely to use a higher powered cartridge to defeat body armor or medium-light cover. They
are more commonly (but not a lot more) bolt-action, as they are simpler to build and maintain.
Also, due to fewer moving and overall parts, they are much more reliable under adverse
conditions. They may also have a more powerful scope to acquire targets further away. Overall,
sniper units never became prominent until World War 1, when the Germans displayed their
usefulness on the battlefield. Since then, they have become irrevocably embedded in warfare.
Examples of sniper rifles include the Accuracy International AWM, Sako TRG-42 and the CheyTac
M200. Examples of specialized sniper cartridges include the .338 Lapua Magnum, .300 Winchester
Magnum, and .408 CheyTac rounds.=====Submachine guns=====A submachine gun is a magazine-fed firearm,
usually smaller than other automatic firearms, that fires pistol-caliber ammunition; for
this reason certain submachine guns can also be referred to as 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 and Heckler & Koch MP5 which use the 9×19mm Parabellum cartridge,
and the American Thompson submachine gun which fires .45 ACP. 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.
Submachine guns were originally about the size of carbines. Because they fire pistol
ammunition, they have limited long-range use, but in close combat can be used in fully automatic
in a controllable manner due to the lighter recoil of the pistol ammunition. They are
also extremely inexpensive and simple to build in time of war, enabling a nation to quickly
arm its military. In the latter half of the 20th century, submachine guns were being miniaturized
to the point of being only slightly larger than some 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 Maschinenpistole
5, or Machine Pistol 5), although some reserve this designation for even smaller submachine
guns such as the MAC-10 and Glock 18, which are about the size and shape of pistols.=====Automatic rifles=====An automatic rifle is a magazine-fed firearm,
wielded by a single infantryman, that is chambered for rifle cartridges and capable of automatic
fire. The M1918 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 Fedorov Avtomat and the
Huot Automatic Rifle. Later, 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 basis for the “assault rifle” subclass of automatic weapons, as contrasted
with “battle rifles”, which generally fire a traditional “full-power” rifle cartridge.=====Assault rifles=====In World War II, Germany introduced the StG
44, and brought to the forefront of firearm technology what eventually became the class
of firearm most widely adopted by the military, the assault rifle. An assault rifle is usually
slightly smaller than a battle rifle such as the American M14, but the chief differences
defining an assault rifle are select-fire capability and the use of a rifle round of
lesser power, known as an intermediate cartridge. Soviet engineer Mikhail Kalashnikov quickly
adapted the German concept, using a less-powerful 7.62×39mm cartridge derived from the standard
7.62×54mmR Russian battle rifle round, to produce the AK-47, which has become the world’s
most widely used assault rifle. Soon after World War II, the Automatic Kalashnikov AK-47
assault rifle began to be fielded by the Soviet Union and its allies in the Eastern Bloc,
as well as by nations such as China, North Korea, and North Vietnam.
In the United States, the assault rifle design was later in coming; the replacement for the
M1 Garand of WWII was another John Garand design chambered for the new 7.62×51mm NATO
cartridge; the select-fire M14, which was used by the U.S. military until the 1960s.
The significant recoil of the M14 when fired in full-automatic mode was seen as a problem
as it reduced accuracy, and in the 1960s it was replaced by Eugene Stoner’s AR-15, which
also marked a switch from the powerful .30 caliber cartridges used by the U.S. military
up until early in the Vietnam War to the much less powerful but far lighter and light recoiling
.223 caliber (5.56mm) intermediate cartridge. The military later designated 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 to conform to B.A.T.F.E. regulations in the
U.S., it lacks the mechanism that permits fully automatic fire.
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 U.S. and NATO tank and vehicle crews, airbornes, support
staff, and in other scenarios where space is limited. The IMI Galil, an Israeli-designed
weapon based on the action of the AK-47, is in use by Israel, Italy, Burma, the Philippines,
Peru, and Colombia. Swiss Arms of Switzerland produces the SIG SG 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.
Modern designs call for compact weapons retaining firepower. The bullpup design, by mounting
the magazine behind the trigger, unifies the accuracy and firepower of the traditional
assault rifle with the compact size of the submachine gun (though submachine guns are
still used); examples are the French FAMAS and the British SA80.=====Personal defense weapons=====A recently developed class of firearm is the
personal defense weapon or PDW, which is in simplest terms a submachine gun designed to
fire ammunitions with ballistic performance similar to rifle cartridges. While a submachine
gun is desirable for its compact size and ammunition capacity, its pistol cartridges
lack the penetrating capability of a rifle round. Conversely, rifle bullets can pierce
light armor and are easier to shoot accurately, but even a carbine such as the Colt M4 is
larger and/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 (often specially designed for the weapon), thus combining the advantages of a carbine
and submachine gun. This also earned the PDWs an infrequently used nickname — the submachine
carbines. The FN P90 and Heckler & Koch MP7 are most famous examples of PDWs.=====Battle rifles=====Battle rifles are another subtype of rifle,
usually defined as selective fire rifles that use full power rifle cartridges, examples
of which include the 7.62x51mm NATO, 7.92x57mm Mauser, and 7.62x54mmR. These serve similar
purposes to assault rifles, as they both are usually employed by ground infantry. However,
some prefer battle rifles due to their more powerful cartridge, despite added recoil.
Some semi-automatic sniper rifles are configured from battle rifles.===Function===Firearms are also categorized by their functioning
cycle or “action” which describes its loading, firing, and unloading cycle.====Manual====
The earliest evolution of the firearm, there are many types of manual action firearms.
These can be divided into two basic categories: single shot and repeating.
A single shot firearm can only be fired once per equipped barrel before it must be reloaded
or charged via an external mechanism or series of steps. A repeating firearm can be fired
multiple times, but can only be fired once with each subsequent pull of the trigger.
Between trigger pulls, the firearm’s action must be reloaded or charged via an internal
mechanism.====Lever action========Pump action========Semi-automatic====A semi-automatic, self-loading, or “auto loader”
firearm is one that performs all steps necessary to prepare it for firing again after a single
discharge, until cartridges are no longer available in the weapon’s feed device or magazine.
Auto loaders fire one round with each pull of the trigger. Some people confuse the term
with “fully automatic” firearms. (See next.) While some semi-automatic rifles may resemble
military-style firearms, they are not properly classified “Assault Weapons” which refers
to those that continue to fire until the trigger is no longer depressed.====Automatic====
An automatic firearm, or “fully automatic”, “fully auto”, or “full auto”, is generally
defined as one that continues to load and fire cartridges from its magazine as long
as the trigger is depressed (and until the magazine is depleted of available ammunition.)
The first weapon generally considered in this category is the Gatling gun, originally a
carriage-mounted, crank-operated firearm with multiple rotating barrels that was fielded
in the American Civil War. The modern trigger-actuated machine gun began with various designs developed
in the late 19th century and fielded in World War I, such as the Maxim gun, Lewis Gun, and
MG 08 “Spandau”. Most automatic weapons are classed as long guns (as the ammunition used
is of similar type as for rifles, and the recoil of the weapon’s rapid fire is better
controlled with two hands), but handgun-sized automatic weapons also exist, generally in
the “submachine gun” or “machine pistol” class.====Selective fire====Selective fire, or “select fire”, means the
capability of a weapon’s fire control to be adjusted in either semi-automatic, fully automatic
firing modes, or 3 round burst. The modes are chosen by means of a selector, which varies
depending on the weapon’s design. Some selective-fire weapons have burst fire mechanisms built in
to limit the maximum number of shots fired in fully automatic mode, with most common
limits being two or three rounds per trigger pull. The presence of selective-fire modes
on firearms allows more efficient use of ammunition for specific tactical needs, either precision-aimed
or suppressive fire. This capability is most commonly found on military weapons of the
20th and 21st centuries, most notably the assault rifles.==Health hazards==Assault by firearm resulted in 173,000 deaths,
globally, in 2015, up from 128,000 deaths in 1990, however this represents a drop in
rate from 2.41/100,000 in 1990 to 2.35/100,000 in 2015, as world population has increased
by more than two billion. Additionally, there were 32,000 unintentional firearm global deaths
in 2015. In 2017, there were 39,773 gun-related deaths in the United States, and over 60%
of suicides in the United States are from firearms. Firearms are the second leading
mechanism of injury deaths, after motor vehicle accidents. To prevent unintentional injury,
gun safety training includes education on proper firearm storage and firearm-handling
etiquette.==History==The first primitive firearms were invented
about 1250 AD in China when the man-portable fire lance (a bamboo or metal tube that could
shoot ignited gunpowder) was combined with projectiles such as scrap metal, broken porcelain,
or darts/arrows.The earliest depiction of a firearm is a sculpture from a cave in Sichuan,
China. The sculpture dates to the 12th century and is of a figure carrying a vase-shaped
bombard, with flames and a cannonball coming out of it. The oldest surviving gun, a hand
cannon made of bronze, has been dated to 1288 because it was discovered at a site in modern-day
Acheng District, Heilongjiang, China, where the Yuan Shi records that battles were fought
at that time. The firearm had a 6.9 inch barrel of a 1-inch diameter, a 2.6 inch chamber for
the gunpowder and a socket for the firearm’s handle. It is 13.4 inches long and 7.8 pounds
without the handle, which would have been made of wood.The Arabs and Mamluks had firearms
in the late 13th century. In the 14th century, firearms were obtained by the Ottoman Turks
and the Europeans. The Koreans adopted firearms from the Chinese in the 14th century. The
Iranians (first Aq Qoyunlu and Safavids) and Indians (first Mughals) all got them no later
than the 15th century, from the Ottoman Turks. The Japanese did not acquire firearms until
the 16th century, and then from the Portuguese rather than the Chinese.The development behind
firearms accelerated during the 19th and 20th centuries. Breech-loading became more or less
a universal standard for the reloading of most hand-held firearms and continues to be
so with some notable exceptions (such as mortars). Instead of loading individual rounds into
weapons, magazines holding multiple munitions were adopted—these aided rapid reloading.
Automatic and semi-automatic firing mechanisms meant that a single soldier could fire many
more rounds in a minute than a vintage weapon could fire over the course of a battle. Polymers
and alloys in firearm construction made weaponry progressively lighter and thus easier to deploy.
Ammunition changed over the centuries from simple metallic ball-shaped projectiles that
rattled down the barrel to bullets and cartridges manufactured to high precision. Especially
in the past century has particular attention been devoted to accuracy and sighting to make
firearms altogether far more accurate than ever before. More than any single factor though,
firearms have proliferated due to the advent of mass production—enabling arms manufacturers
to produce large quantities of weaponry to a consistent standard.The force of a projectile
is related to the kinetic energy imparted to it, given by the formula E k=1
2 m v 2 {\displaystyle E_{\text{k}}={\tfrac {1}{2}}mv^{2}}
where m {\displaystyle m}
is the mass and v {\displaystyle v}
is the velocity of the projectile.Generally, kinetic energy can be enhanced in two ways: By increasing the mass of the bullet, either
by increasing caliber (and thus size and weight), or by using denser materials like uranium
or tungsten. By increasing the projectile’s velocity, through
better or larger propellant charges, through better manufacturing tolerances and materials
in bullet and barrel, or through longer barrels.Velocities of bullets increased with the use of a “jacket”
of a metal such as copper or copper alloys that covered a lead core and allowed the bullet
to glide down the barrel more easily than exposed lead. Such bullets are designated
as “full metal jacket” (FMJ). Such FMJ bullets are less likely to fragment on impact and
are more likely to traverse through a target while imparting less energy. Hence, FMJ bullets
impart less tissue damage than non-jacketed bullets that expand. (Dougherty and Eidt,
2009) This led to their adoption for military use by countries adhering to the Hague Convention
in 1899.That said, the basic principle behind firearm operation remains unchanged to this
day. A musket of several centuries ago is still similar in principle to a modern-day
assault rifle—using the expansion of gases to propel projectiles over long distances—albeit
less accurately and rapidly.===Evolution=======
Early models=========
Fire lances=====The Chinese fire lance was the direct predecessor
to the modern concept of the firearm. It was not a gun itself, but an addition to the soldiers’
spears. Originally it consisted of paper or bamboo barrels that would have incendiary
gunpowder within it, that could be lit one time and would project flames at the enemy.
Sometimes the Chinese troops would place small projectiles within the barrel that would also
be projected when the gunpowder was lit, but most of the explosive force would create flames.
Later, the barrel was changed to be made of metal, so that a more explosive gunpowder
could be used and put more force into the propulsion of the projectile.=====Hand cannons=====The original predecessor of all firearms,
the Chinese fire lance and hand cannon were 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 lit, 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 could be absorbed by bracing the barrel against the ground using
a wooden support, the forerunner of the stock. Neither the quality or amount of gunpowder,
nor the consistency in projectile dimensions were controlled, with resulting inaccuracy
in firing due to windage, variance in gunpowder composition, and 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.=====Muskets=====Muzzle-loading muskets (smooth-bored long
guns) were among the first firearms 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”
with superposed loads. 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.====Loading techniques====Most early firearms were muzzle-loading. This
form of loading has several disadvantages, such as a slow rate of fire and having to
expose oneself to enemy fire to reload as the weapon had to be pointed upright so the
powder could be poured through the muzzle into the breech followed by the ramming the
projectile into the breech. As effective methods of sealing the breech were developed through
the development of sturdy, weatherproof, self-contained metallic cartridges, muzzle-loaders were replaced
by single-shot breech loaders. Eventually single-shot weapons were replaced by the following
repeater type weapons.====Internal magazines====Many firearms made in the late 19th century
through the 1950s used internal magazines to load the cartridge into the chamber of
the weapon. The most notable and revolutionary weapons of this period appeared during the
U.S. Civil War and they were the Spencer and Henry repeating rifles. Both used fixed tubular
magazines, the former having the magazine in the buttstock and the latter under the
barrel which allowed a larger capacity. Later weapons used fixed box magazines that could
not be removed from the weapon without disassembling the weapon itself. Fixed magazines permitted
the use of larger cartridges and eliminated the hazard of having the bullet of one cartridge
butting next to the primer or rim of another cartridge. These magazines are loaded while
they are in the weapon, often using a stripper clip. A clip is used to transfer cartridges
into the magazine. Some notable weapons that use internal magazines include the Mosin–Nagant,
the Mauser Kar 98k, the Springfield M1903, the M1 Garand, and the SKS. Firearms that
have internal magazines are usually, but not always, rifles. Some exceptions to this include
the Mauser C96 pistol, which uses an internal magazine, and the Breda 30, an Italian light
machine gun.====Detachable magazines====
Many modern firearms use what are called detachable or box magazines as their method of chambering
a cartridge. Detachable magazines can be removed from the weapon without disassembling the
firearms, usually by pushing the magazine release.====Belt-fed weapons====A belt or ammunition belt is a device used
to retain and feed cartridges into a firearm commonly used on machine guns. Belts were
originally composed of canvas or cloth with pockets spaced evenly to allow the belt to
be mechanically fed into the gun. These designs were prone to malfunctions due to the effects
of oil and other contaminants altering the belt. Later belt designs used permanently
connected metal links to retain the cartridges during feeding. These belts were more tolerant
to exposure to solvents and oil. Some notable weapons that use belts are the M240, the M249,
the M134 Minigun, and the PK Machine Gun.====Firing mechanisms=========
Matchlock=====Matchlocks were the first and simplest firearms
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 main parts to the matchlock
firing mechanism are the pan, match, arm and trigger. A benefit of the pan and arm swivel
being moved to the side of the gun was it gave a clear line of fire. An advantage to
the matchlock firing mechanism is that it did not misfire. However, it also came with
some disadvantages. One disadvantage was if it was raining the match could not be kept
lit to fire the weapon. Another issue with the match was it could give away the position
of soldiers because of the glow, sound, and smell.=====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 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 wheellock action was an innovation that was not widely adopted
due to the high cost of the clockwork mechanism.=====Flintlock=====The flintlock action was a major innovation
in firearm 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 lock) The flintlock was widely used during
the 17th, 18th, and 19th centuries in both muskets and rifles.=====Percussion cap=====Percussion caps (caplock mechanisms), coming
into wide service in the early 19th century, were a dramatic improvement over flintlocks.
With the percussion cap mechanism, the small primer charge of gunpowder used in all preceding
firearms 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 anything.) In the case of percussion
caps the hammer was hollow on the end to fit around the cap in order to keep the cap from
fragmenting and injuring the shooter. Once struck, 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 firearms.====Cartridges====Frenchman Louis-Nicolas Flobert invented the
first rimfire metallic cartridge in 1845. His cartridge consisted of a percussion cap
with a bullet attached to the top. Flobert then made what he called “parlor guns” for
this cartridge, as these rifles and pistols were designed to be shot in indoor shooting
parlors in large homes. These 6mm Flobert cartridges, do not contain any powder, the
only propellant substance contained in the cartridge is the percussion cap. In English-speaking
countries, the 6mm Flobert cartridge corresponds to .22 BB Cap and .22 CB Cap ammunition. These
cartridges have a relatively low muzzle velocity of around 700 ft/s (210 m/s).
This was major innovation in firearms ammunition, previously delivered as separate bullets and
powder, was combined in a single metallic (usually brass) cartridge containing a percussion
cap, powder, and a bullet in one weatherproof package. The main technical advantage of the
brass cartridge case was the effective and reliable sealing of high pressure gasses at
the breech, as the gas pressure forces the cartridge case to expand outward, pressing
it firmly against the inside of the gun barrel chamber. This prevents the leakage of hot
gas which could injure the shooter. The brass cartridge also opened the way for modern repeating
arms, by uniting the bullet, gunpowder and primer into one assembly that could be fed
reliably into the breech by a mechanical action in the firearm.
Before this, a “cartridge” was simply a premeasured quantity of gunpowder together with a ball
in a small cloth bag (or rolled paper cylinder), 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, operating at considerably
higher pressures than rimfire cartridges. Centerfire cartridges are also safer, as a
dropped rimfire cartridge has the potential to discharge if its rim strikes the ground
with sufficient force to ignite the primer. This is practically impossible with most centerfire
cartridges. 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 defined as a part of the firearm which exists to store
ammunition and assist in its feeding by the action into the breech (such as through the
rotation of a revolver’s cylinder or by spring-loaded platforms in most pistol and rifle designs).
Some magazines, such as that of most centerfire hunting rifles and all revolvers, are internal
to and inseparable from the firearm, and are loaded by using a “clip”. A clip, often mistakingly
used to refer to a detachable “magazine”, is a device that holds the ammunition by the
rim of the case and is designed to assist the shooter in reloading the firearm’s magazine.
Examples include revolver speedloaders, the stripper clip used to aid loading rifles such
as the Lee–Enfield or Mauser 98, and the en-bloc clip used in loading the M1 Garand.
In this sense, “magazines” and “clips”, though often used synonymously, refer to different
types of devices.====Repeating, semi-automatic, and automatic
firearms====Many firearms are “single shot”: i.e., each
time a cartridge is fired, the operator must manually re-cock the firearm and load another
cartridge. The classic single-barreled shotgun is a good example. A firearm that can load
multiple cartridges as the firearm is re-cocked is considered a “repeating firearm” or simply
a “repeater”. A lever-action rifle, a pump-action shotgun, and most bolt-action rifles are good
examples of repeating firearms. A firearm that automatically re-cocks and reloads the
next round with each trigger pull is considered a semi-automatic or autoloading firearm.
The first “rapid firing” firearms 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, thus the operator needed only to pull a trigger (which made the firing mechanisms
truly “automatic”). An automatic (or “fully automatic”) firearm is one that automatically
re-cocks, reloads, and fires as long as the trigger is depressed. An automatic firearm
is capable of firing multiple rounds with one pull of the trigger. The Gatling gun 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 rifles such as the Browning Automatic Rifle 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. Many modern military firearms
have a selective fire option, which is a mechanical switch that allows the firearm be fired either
in the semi-automatic or fully automatic mode. In the current M16A2 and M16A4 variants of
the U.S.-made M16, continuous fully automatic fire is not possible, having been replaced
by an automatic burst of three cartridges (this conserves ammunition and increases controllability).
Automatic weapons are largely restricted to military and paramilitary organizations, though
many automatic designs are infamous for their use by civilians.==See also

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