Machine gun
Encyclopedia
Automatic firearm
An automatic firearm is a firearm that loads another round mechanically after the first round has been fired.The term can be used to refer to semi-automatic firearms, which fire one shot per single pull of the trigger , or fully automatic firearms, which will continue to load and fire ammunition...
mounted or portable firearm
Firearm
A firearm is a weapon that launches one, or many, projectile at high velocity through confined burning of a propellant. This subsonic burning process is technically known as deflagration, as opposed to supersonic combustion known as a detonation. In older firearms, the propellant was typically...
, usually designed to fire rounds in quick succession from an ammunition belt
Belt (firearm)
A belt or ammunition belt is a device used to retain and feed cartridges into a firearm. Belts and the associated feed systems are typically employed to feed machine guns or other automatic weapons...
or large-capacity magazine
Magazine (firearm)
A magazine is an ammunition storage and feeding device within or attached to a repeating firearm. Magazines may be integral to the firearm or removable . The magazine functions by moving the cartridges stored in the magazine into a position where they may be loaded into the chamber by the action...
, typically at a rate of several hundred rounds per minute.
Machine guns are generally categorized as sub-machine guns, machine guns, or autocannon
Autocannon
An autocannon or automatic cannon is a rapid-fire projectile weapon firing a shell as opposed to the bullet fired by a machine gun. Autocannons often have a larger caliber than a machine gun . Usually, autocannons are smaller than a field gun or other artillery, and are mechanically loaded for a...
s. Sub-machine guns are designed to be portable automatic weapons for personal defense or short range combat, and are intended to be fired while being hand held. Submachine guns use small pistol
Handgun
A handgun is a firearm designed to be held and operated by one hand. This characteristic differentiates handguns as a general class of firearms from long guns such as rifles and shotguns ....
caliber rounds. A proper machine gun is often portable to a certain degree, but is generally used when mounted on a stand or fired from the ground on a bipod
Bipod
A bipod is a support device that is similar to a tripod or monopod, but with two legs. It provides significant stability along two axes of motion .-Firearms:...
. Light machine guns can be fired hand held like a rifle
Rifle
A rifle is a firearm designed to be fired from the shoulder, with a barrel that has a helical groove or pattern of grooves cut into the barrel walls. The raised areas of the rifling are called "lands," which make contact with the projectile , imparting spin around an axis corresponding to the...
, but the gun is more effective when fired from a prone position. Proper machine guns use larger caliber rifle rounds. The difference between machine guns and autocannons is based on caliber
Caliber
In guns including firearms, caliber or calibre is the approximate internal diameter of the barrel in relation to the diameter of the projectile used in it....
, with autocannons using calibers larger than 16 mm.
Another factor is whether the gun fires conventional rounds or explosive
Explosive material
An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure...
rounds. Guns firing large-caliber explosive rounds are generally considered either autocannons or automatic grenade launchers ("grenade machine guns"). By contrast with the other two categories (sub-machine guns and autocannons), machine guns (like rifles) tend to share the characteristic of a very high ratio of barrel length to caliber (a long barrel for a small caliber); indeed, a true machine gun is essentially a fully automatic rifle, and the boundaries between the two are often blurred. Often, the criterion for a machine gun as opposed to an automatic rifle is considered to be the presence of a quick change barrel or other cooling system (see below).
In United States gun law
Gun law in the United States
Gun law in the United States is defined by a number of state and federal statutes. In the United States of America, the protection against infringement of the right to keep and bear arms is addressed in the Second Amendment to the United States Constitution...
, machine gun is a term of art for any fully automatic firearm, and also for any component or part that will modify an existing firearm such that it functions as a fully automatic firearm.
Overview of modern automatic machine guns
Unlike semi-automatic firearmSemi-automatic firearm
A semi-automatic, or self-loading firearm is a weapon which performs all steps necessary to prepare the weapon to fire again after firing—assuming cartridges remain in the weapon's feed device or magazine...
s, which require one trigger pull per bullet fired, a machine gun is designed to fire as long as the trigger is held down. Nowadays the term is restricted to relatively heavy weapons fired from some sort of support rather than hand-held, able to provide continuous or frequent bursts of automatic fire for as long as ammunition lasts. Machine guns are normally used against unprotected or lightly protected personnel, or to provide suppressive fire
Suppressive fire
In military science, suppressive fire is a fire that degrades the performance of a target below the level needed to fulfill its mission. Suppression is usually only effective for the duration of the fire. Suppressive fire is not always a direct form of fire towards targets; it can be an effective...
.
Some machine guns have in practice maintained suppressive fire almost continuously for hours; other automatic weapons overheat after less than a minute of use. Because they become very hot, practically all machine guns fire from an open bolt
Open bolt
A semi or full automatic firearm is said to fire from an open bolt if, when ready to fire, the bolt and working parts are held to the rear. When the trigger is pulled the bolt goes forward, feeding a round from the magazine into the chamber and firing it...
, to permit air cooling from the breech
Breech-loading weapon
A breech-loading weapon is a firearm in which the cartridge or shell is inserted or loaded into a chamber integral to the rear portion of a barrel....
between bursts. They also have either a barrel cooling system, or removable barrels which allow a hot barrel to be replaced.
Although subdivided into "light
Light machine gun
A light machine gun is a machine gun designed to be employed by an individual soldier, with or without an assistant, as an infantry support weapon. Light machine guns are often used as squad automatic weapons.-Characteristics:...
", "medium
Medium machine gun
A medium machine gun or MMG, in modern terms, usually refers to a belt-fed automatic firearm firing a full-power rifle cartridge.-History:...
", "heavy
Heavy machine gun
The heavy machine gun or HMG is a larger class of machine gun generally recognized to refer to two separate stages of machine gun development. The term was originally used to refer to the early generation of machine guns which came into widespread use in World War I...
" or "general-purpose", even the lightest machine guns tend to be substantially larger and heavier than other automatic weapons. Squad automatic weapon
Squad automatic weapon
A squad automatic weapon is a weapon used to give infantry squads or sections a portable source of automatic firepower. Weapons used in this role are selective-fire rifles, usually fitted with a bipod and heavier barrel to perform as Light machine guns...
s (SAW) are a variation of light machine gun
Light machine gun
A light machine gun is a machine gun designed to be employed by an individual soldier, with or without an assistant, as an infantry support weapon. Light machine guns are often used as squad automatic weapons.-Characteristics:...
and require only one operator (sometimes with an assistant to carry ammunition). Medium and heavy machine guns are either mounted on a tripod or on a vehicle; when carried on foot, the machine gun and associated equipment (tripod, ammunition, spare barrels) require additional crew members.
According to U.S. Army doctrine, a machine gun is distinguished from an automatic rifle by how it is used: a machine gun is a crew-served weapon, while an automatic rifle is used by a single person. While most weapons are designed to be used exclusively in one manner or the other, FM 3-22.68 "Crew-Served Machine Guns", describes how the M249 can be used either as a machine gun or as an automatic rifle: "Both the M249 automatic rifle and the M249 machine gun are identical, but its employment is different. The M249 automatic rifle is operated by an automatic rifleman, but its ammunition may be carried by other Soldiers within the squad or unit. The M249 machine gun is a crew-served weapon."
The majority of machine guns are belt-fed
Belt (firearm)
A belt or ammunition belt is a device used to retain and feed cartridges into a firearm. Belts and the associated feed systems are typically employed to feed machine guns or other automatic weapons...
, although some light machine guns are fed from drum
Drum magazine
A drum magazine is a type of firearms magazine that is cylindrical in shape, similar to a drum. Instead of rounds being stored flat, as in a more common box magazine, rounds in a drum magazine are stored in a spiral around the center of the magazine, facing the direction of the barrel.There are...
or box magazines
Magazine (firearm)
A magazine is an ammunition storage and feeding device within or attached to a repeating firearm. Magazines may be integral to the firearm or removable . The magazine functions by moving the cartridges stored in the magazine into a position where they may be loaded into the chamber by the action...
, and some vehicle-mounted machine guns are hopper-fed.
Other automatic weapons are subdivided into several categories based on the size of the bullet used, and whether the cartridge
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
is fired from a positively locked closed bolt
Closed bolt
A semi or full-automatic firearm which is said to fire from a closed bolt is one where, when ready to fire, a round is in the chamber and the bolt and working parts are forward...
, or a non-positively locked open bolt
Open bolt
A semi or full automatic firearm is said to fire from an open bolt if, when ready to fire, the bolt and working parts are held to the rear. When the trigger is pulled the bolt goes forward, feeding a round from the magazine into the chamber and firing it...
. Full automatic firearms using pistol-caliber ammunition are called machine pistol
Machine pistol
A machine pistol is a handgun-style, often magazine-fed and self-loading firearm, capable of fully automatic or burst fire, and normally chambered for pistol cartridges. The term is a literal translation of Maschinenpistole, the German term for a hand-held automatic weapon...
s or submachine guns largely on the basis of size. Selective fire
Selective fire
A selective fire firearm has at least one semi–automatic and one automatic mode, which is activated by means of a selector which varies depending on the weapon's design. Some selective fire weapons utilize burst fire mechanisms to limit the maximum or total number of shots fired automatically in...
rifles firing a full-power rifle cartridge from a closed bolt are called automatic rifle
Automatic rifle
Automatic rifle is a term generally used to describe a semi-automatic rifle chambered for a rifle cartridge, capable of delivering both semi- and full automatic fire...
s or battle rifle
Battle rifle
A battle rifle is a military service rifle that fires a full power rifle cartridge, such as 7.62x51mm NATO. While the designation of battle rifle is usually given to post-World War II select fire infantry rifles such as the H&K G3, the FN FAL or the M14, this term can also apply to older military...
s, while rifles that fire an intermediate cartridge (see below) are called assault rifle
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...
s. The difference in construction was driven by the difference in intended deployment. Automatic rifles (such as the Browning Automatic Rifle
Browning Automatic Rifle
The Browning Automatic Rifle was a family of United States automatic rifles and light machine guns used by the United States and numerous other countries during the 20th century. The primary variant of the BAR series was the M1918, chambered for the .30-06 Springfield rifle cartridge and designed...
) were designed to be a high duty cycle arm for support of other troops, and were often made and deployed with quick change barrel assemblies to allow quick replacement of over heated barrels to allow for continued fire, and may have been operated by both the person actually firing the weapon as well as an additional crewman to assist in providing and caring for ammunition and the barrels, similar to a reduced version of a squad weapon (above). The assault rifle generally was made for a more intermittent duty cycle, and was designed to be easily carried and used by a single person.
Assault rifle
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...
s are a compromise between the size and weight of pistol-caliber submachinegun and a full size traditional automatic rifle by firing intermediate cartridges, (or sometimes full power cartridges) and allowing semi-automatic, burst or full-automatic fire options (selective fire), often with two or more of these available on the rifle at once. The modern legal definition of "assault rifle" is of significance in states like California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, where according to state law, certain weapons that cosmetically resemble true assault rifles, but are only capable of semi-automatic (or autoloading), are categorized as "assault weapon
Assault weapon
Assault weapon is a non-technical term referring to any of a broad category of firearms with certain features, including some semiautomatic rifles, some pistols, and some shotguns. There are a variety of different statutory definitions of assault weapons in local, state, and federal laws in the...
s" and are illegal to purchase or own by civilian residents of the state, even after a less restrictive ban by the federal government was allowed to lapse after having no impact on these weapons' use in crime. Therefore, supporters of gun rights generally consider the use of the phrase "assault weapon" to be pejorative when used to describe these civilian firearms, and this term is seldom used outside of the United States in this context.
The machine gun's primary role in modern ground combat is to provide suppressive fire
Suppressive fire
In military science, suppressive fire is a fire that degrades the performance of a target below the level needed to fulfill its mission. Suppression is usually only effective for the duration of the fire. Suppressive fire is not always a direct form of fire towards targets; it can be an effective...
on an opposing force's position, forcing the enemy to take cover and reducing the effectiveness of his fire. This either halts an enemy attack or allows friendly forces to attack enemy positions with less risk.
Light machine guns usually have simple iron sights. A common aiming system is to alternate solid ("ball") rounds and tracer ammunition
Tracer ammunition
Tracer ammunition are bullets that are built with a small pyrotechnic charge in their base. Ignited by the burning powder, the phosphorus tail burns very brightly, making the projectile visible to the naked eye...
rounds (usually one tracer round for every four ball rounds), so shooters can see the trajectory and "walk" the fire into the target, and direct the fire of other soldier
Soldier
A soldier is a member of the land component of national armed forces; whereas a soldier hired for service in a foreign army would be termed a mercenary...
s.
Many heavy machine gun
Heavy machine gun
The heavy machine gun or HMG is a larger class of machine gun generally recognized to refer to two separate stages of machine gun development. The term was originally used to refer to the early generation of machine guns which came into widespread use in World War I...
s, such as the Browning M2 .50 caliber machine gun, are accurate enough to engage targets at great distances. During the Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...
, Carlos Hathcock
Carlos Hathcock
Carlos Hathcock was a United States Marine Corps Gunnery Sergeant sniper with a service record of 93 confirmed kills. Hathcock's record and the extraordinary details of the missions he undertook made him a legend in the Marine Corps...
set the record for a long-distance shot
Longest recorded sniper kills
Reports regarding the longest recorded sniper kill that contain information regarding the shooting distance and the identity of the sniper have been presented to the general public since 1967. Snipers in modern warfare have had a long history since the development of long distance weaponry...
at 7382 ft (2250 m) with a .50 caliber heavy machine gun he had equipped with a telescopic sight
Telescopic sight
A telescopic sight, commonly called a scope, is a sighting device that is based on an optical refracting telescope. They are equipped with some form of graphic image pattern mounted in an optically appropriate position in their optical system to give an accurate aiming point...
. This led to the introduction of .50 caliber anti-materiel sniper rifles
Anti-materiel rifle
An anti-materiel rifle is a rifle that is designed for use against military equipment rather than against other combatants ....
, such as the Barrett M82.
Operation
All machine guns follow a cycle:- Pulling (manually or electrically) the bolt assembly/bolt carrier rearward by way of the cocking lever to the point bolt carrier engages a sear and stays at rear position until trigger is activated making bolt carrier move forward
- Loading fresh round into chamber and locking bolt
- Firing round by way of a firing pin or striker (except for aircraft medium caliber using electric ignition primers) hitting the primer that ignites the powder when bolt reaches locked position.
- Unlocking and removing the spent case from the chamber and ejecting it out of the weapon as bolt is moving rearward
- Loading the next round into the firing chamber. Usually the recoil spring aka main springSpring (device)A spring is an elastic object used to store mechanical energy. Springs are usually made out of spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication...
tension pushes bolt back into battery and a camCamA cam is a rotating or sliding piece in a mechanical linkage used especially in transforming rotary motion into linear motion or vice-versa. It is often a part of a rotating wheel or shaft that strikes a lever at one or more points on its circular path...
strips the new round from a feeding device, belt or box. - Light machine guns can be held like a rifle.
Cycle is repeated as long as the trigger is activated by operator.
Releasing the trigger resets the trigger mechanism by engaging a sear so the weapon stops firing with bolt carrier fully at the rear.
The operation is basically the same for all semi automatic or automatic weapons, regardless of the means of activating these mechanisms. Some examples:
- Machine pistols and submachine gunSubmachine gunA submachine gun is an automatic carbine, designed to fire pistol cartridges. It combines the automatic fire of a machine gun with the cartridge of a pistol. The submachine gun was invented during World War I , but the apex of its use was during World War II when millions of the weapon type were...
s (like the World War IIWorld War IIWorld War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
"grease gunM3 submachine gunThe M3 was an American .45-caliber submachine gun adopted for U.S. Army service on 12 December 1942, as the United States Submachine Gun, Cal. .45, M3. The M3 was designed as a more cost-effective alternative to the Thompson, optimized for mass production...
", MAC-10MAC-10The MAC-10 is a highly compact, blowback operated machine pistol developed by Gordon B. Ingram in 1964.-Design:The M-10 was built predominantly from steel stampings...
or the UziUzi submachine gunThe Uzi is a family of Israeli open bolt, blowback-operated submachine guns. Smaller variants are considered to be machine pistols. The Uzi was one of the first weapons to use a telescoping bolt design which allows for the magazine to be housed in the pistol grip for a shorter weapon.The first Uzi...
) are usually blowbackBlowback (arms)Blowback is a system of operation for self-loading firearms that obtains energy from the motion of the cartridge case as it is pushed to the rear by expanding gases created by the ignition of the propellant charge....
operated.
- Most assault rifleAssault rifleAn assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...
s and squad automatic weaponSquad automatic weaponA squad automatic weapon is a weapon used to give infantry squads or sections a portable source of automatic firepower. Weapons used in this role are selective-fire rifles, usually fitted with a bipod and heavier barrel to perform as Light machine guns...
s are gas operatedGas-operated reloadingGas-operation is a system of operation used to provide energy to operate autoloading firearms. In gas-operation, a portion of high pressure gas from the cartridge being fired is used to power a mechanism to extract the spent case and chamber a new cartridge. Energy from the gas is harnessed...
. Some weapons, such as the AR-15AR-15The AR-15 is a lightweight, 5.56 mm, air-cooled, gas-operated, magazine-fed semi-automatic rifle, with a rotating-lock bolt, actuated by direct impingement gas operation. It is manufactured with the extensive use of aluminum alloys and synthetic materials....
/M16M16 rifleThe M16 is the United States military designation for the AR-15 rifle adapted for both semi-automatic and full-automatic fire. Colt purchased the rights to the AR-15 from ArmaLite, and currently uses that designation only for semi-automatic versions of the rifle. The M16 fires the 5.56×45mm NATO...
, do not have a piston, instead using a system of direct impingement in which the gases operate the bolt carrier by acting directly on it. Others, like the original SA80SA80The SA80 is a British family of 5.56mm small arms. It is a selective fire, gas-operated assault rifle. SA80 prototypes were trialled in 1976 and production was completed in 1994....
patterns, have a bolt carrier that is unlocked and operated by a piston actuated by gases.
- A recoil actuatedRecoil operationRecoil operation is an operating mechanism used in locked-breech, autoloading firearms. As the name implies, these actions use the force of recoil to provide energy to cycle the action...
machine gun uses the recoilRecoilRecoil is the backward momentum of a gun when it is discharged. In technical terms, the recoil caused by the gun exactly balances the forward momentum of the projectile and exhaust gasses, according to Newton's third law...
to first unlock and then operate the action. Heavy machine guns, such as the M2 .50 and BrowningBrowning Arms CompanyBrowning Arms Company is a maker of firearms, bows and fishing gear. Founded in Utah in 1927, it offers a wide variety of firearms, including shotguns, rifles, pistols, and rimfire firearms and sport bows, as well as fishing rods and reels....
.50, are of this type. A cam, lever or actuator demultiplicates the energy of the recoil to operate the bolt.
- An externally actuated machine gun uses an external power source, such as an electric motor or even a hand crank to move its mechanism through the firing sequence. Most modern weapons of this type are called Gatling gunGatling gunThe Gatling gun is one of the best known early rapid-fire weapons and a forerunner of the modern machine gun. It is well known for its use by the Union forces during the American Civil War in the 1860s, which was the first time it was employed in combat...
s in reference to their driving mechanism. Gatling guns have several barrels on a rotating carousel and a system of cams that load, cock, and fire each mechanism progressively as it rotates through the sequence. The continuous nature of the rotary action allows for an incredibly high cyclic rate of fire, often several thousand rounds per minute. Rotary guns are less prone to jamming than a gun operated by gas or recoil, as the external power source will eject misfired rounds with no further trouble, but this is not possible if the force needed to eject the round comes from the round itself. Rotary guns are generally used with large shells, 20 mm in diameter or more, offering benefits of reliability and firepower, though the weight and size of the power source and driving mechanism makes them impractical for use outside of a vehicle or aircraft mount.
- Revolver cannonRevolver cannonA revolver cannon is a type of autocannon commonly used as an aircraft gun. It uses a cylinder with multiple chambers, like those of a revolver handgun, to speed up the loading-firing-ejection cycle. Some examples are also power-driven, to further speed the loading process, but this is by no means...
were developed in World War II by the Germans as the Mauser MK 213 to provide high-caliber cannon with a reasonable rate of fire and reliability. A recoil-operated carriage holds a revolving chamber with typically five chambers. As each round is fired, electrically, the carriage moves back rotating the chamber which also ejects the spent case, indexes the next live round to be fired with the barrel and loads the next round into the chamber. The action is very similar to that of the revolver pistols common in the 19th and 20th centuries, giving this type of weapon its name.
Firing a machine gun produces great amounts of heat. In a worst-case scenario this may cause a cartridge to fire even when the trigger is not pulled, potentially leading to damage or causing the gun to cycle its action and keep firing until it has exhausted its ammunition supply or jammed. To prevent this, some kind of cooling system is required. Early heavy machine guns were often water-cooled; while very effective, the water also added considerable weight to an already bulky design. Air-cooled machine guns feature quick-change barrels, often carried by a crew member. The higher the rate of fire, the more often barrels must be changed and allowed to cool. To minimize this, most air-cooled guns are fired only in short bursts or at a reduced rate of fire. Some designs - such as the many variants of the MG42
MG42
The MG 42 is a 7.9mm universal machine gun that was developed in Nazi Germany and entered service with the Wehrmacht in 1942...
- are capable of rates of fire in excess of 1500 rounds per minute.
In weapons where the round seats and fires at the same time, mechanical timing is essential for operator safety, to prevent the round from firing before it is seated properly. Machine guns are controlled by one or more mechanical sears. When a sear is in place, it effectively stops the bolt at some point in its range of motion. Some sears stop the bolt when it is locked to the rear. Other sears stop the firing pin from going forward after the round is locked into the chamber.
Almost all weapons have a "safety" sear
Sear (firearm)
In a firearm, the sear is the part of the trigger mechanism which holds the hammer or striker back until the correct amount of pressure has been applied to the trigger; at which point the hammer or striker is released to discharge the weapon...
, which simply keeps the trigger from engaging.
History
It would not be until the mid-19th century that successful machine-gun designs came into existence. The key characteristic of modern machine guns, their relatively high rate of fire and more importantly machine (automatic) loading, came with the Model 1862 Gatling gunGatling gun
The Gatling gun is one of the best known early rapid-fire weapons and a forerunner of the modern machine gun. It is well known for its use by the Union forces during the American Civil War in the 1860s, which was the first time it was employed in combat...
, which was adopted by the United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
. These weapons were still powered by hand; however, this changed with Hiram Maxim's idea of harnessing recoil energy to power reloading in his Maxim machine gun. Dr. Gatling also experimented with electric-motor-powered models; this externally powered machine reloading has seen use in modern weapons as well. The Vandenburg and Miltrailleuse volley (organ) gun
Volley gun
A volley gun is a gun with several barrels for firing a number of shots, either simultaneously or in sequence. They differ from modern machine guns in that they lack automatic loading and automatic fire and are limited by the number of barrels bundled together.In practice the large ones were not...
concepts have been revived partially in the early 21st century in the form of electronically controlled, multibarreled volley guns. It is important to note that what exactly constitutes a machine gun, and whether volley guns are a type of machine gun, and to what extent some earlier types of devices are considered to be like machine guns, is a matter of debate in many cases and can vary depending which language and exact definition is used.
Early rapid-firing weapons
James Puckle
James Puckle was an English inventor, lawyer and writer from London chiefly remembered for his invention of the Defence Gun, better known as the Puckle gun, a multi-shot gun mounted on a stand capable of firing up to nine rounds per minute...
, a London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
lawyer, who patented what he called "The Puckle Gun
Puckle gun
The Puckle gun was invented in 1718 by James Puckle an English inventor, lawyer and writer.-Design and patent:...
" on May 15, 1718. It was a design for a 1 in. (25.4 mm) caliber, flintlock
Flintlock
Flintlock is the general term for any firearm based on the flintlock mechanism. The term may also apply to the mechanism itself. Introduced at the beginning of the 17th century, the flintlock rapidly replaced earlier firearm-ignition technologies, such as the doglock, matchlock and wheellock...
revolver cannon able to fire 9 rounds before reloading, intended for use on ship
Ship
Since the end of the age of sail a ship has been any large buoyant marine vessel. Ships are generally distinguished from boats based on size and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of activities, such as the transport of people or goods, fishing,...
s. According to Puckle, it was able to fire round bullets at Christians and square bullets at Turks. While ahead of its time, foreshadowing the designs of revolvers, it was not adopted or produced.
In 1777, Philadelphia gunsmith
Gunsmith
A gunsmith is a person who repairs, modifies, designs, or builds firearms. This occupation is different from an armorer. The armorer primarily maintains weapons and limited repairs involving parts replacement and possibly work involving accurization...
Joseph Belton offered the Continental Congress
Continental Congress
The Continental Congress was a convention of delegates called together from the Thirteen Colonies that became the governing body of the United States during the American Revolution....
a "new improved gun"
Belton flintlock
The Belton Flintlock was a repeating flintlock design using superposed loads, invented by Philadelphia, Pennsylvania resident Joseph Belton some time prior to 1777...
, which was capable of firing up to twenty shots in five seconds, automatically, and was capable of being loaded by a cartridge
Paper cartridge
Paper cartridge refers to one of various types of small arms ammunition used before the advent of the metallic cartridge. These cartridges consisted of a paper cylinder or cone containing the bullet, gunpowder, and, in some cases, a primer or a lubricating and anti-fouling agent...
. Congress requested that Belton modify 100 flintlock muskets to fire eight shots in this manner, but rescinded the order when Belton's price proved too high.
In the early and mid-19th century, a number of rapid-firing weapons appeared which offered multi-shot fire, and a number of semi-automatic weapons as well as volley gun
Volley gun
A volley gun is a gun with several barrels for firing a number of shots, either simultaneously or in sequence. They differ from modern machine guns in that they lack automatic loading and automatic fire and are limited by the number of barrels bundled together.In practice the large ones were not...
s. Volley guns (such as the Mitrailleuse
Mitrailleuse
Mitrailleuse is the French word used to describe all rapid-firing weapons of rifle caliber. Therefore the word mitrailleuse, when used in the French language, applies to all machine guns including modern full automatic weapons. However in the English language the word mitrailleuse applies to...
) and double barreled pistols relied on duplicating all parts of the gun. Pepperbox pistols did away with needing multiple hammers but used multiple barrels. Revolvers further reduced this to only needing a pre-prepared magazine using the same barrel and ignitions. However, like the Puckle gun, they were still only semiautomatic.
The Agar Gun, otherwise known as a "coffee-mill gun" because of its resemblance to a coffee mill, was invented by Wilson Agar at the beginning of the US Civil War. The weapon featured automatic loading through ammunition being loaded in a hopper above the weapon. The weapon featured a single barrel and fired through the turning of a hand crank. The weapon was demonstrated to President Lincoln in 1861. He was so impressed with the weapon that he purchased 10 on the spot for $1,300 apiece. The Union Army eventually purchased a total of 54 of the weapons. However, due to antiquated views of the Ordnance Department the weapons, like its more famous counterpart the Gatling Gun, saw only limited use.
The Gatling gun
Gatling gun
The Gatling gun is one of the best known early rapid-fire weapons and a forerunner of the modern machine gun. It is well known for its use by the Union forces during the American Civil War in the 1860s, which was the first time it was employed in combat...
, patented in 1861 by Richard Jordan Gatling
Richard Jordan Gatling
Dr. Richard Jordan Gatling was an American inventor best known for his invention of the Gatling gun, the first successful machine gun.-Life:...
, was the first to offer controlled, sequential fire with automatic loading. The design's key features were machine loading of prepared cartridges and a hand-operated crank for sequential high-speed firing. It first saw very limited action in the American Civil War
American Civil War
The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...
; it was subsequently improved and used in the Franco-Prussian war
Franco-Prussian War
The Franco-Prussian War or Franco-German War, often referred to in France as the 1870 War was a conflict between the Second French Empire and the Kingdom of Prussia. Prussia was aided by the North German Confederation, of which it was a member, and the South German states of Baden, Württemberg and...
and North-West Rebellion
North-West Rebellion
The North-West Rebellion of 1885 was a brief and unsuccessful uprising by the Métis people of the District of Saskatchewan under Louis Riel against the Dominion of Canada...
. Many were sold to other armies in the late 19th century and continued to be used into the early 20th century, until they were gradually supplanted by Maxim guns. Early multi-barrel guns were approximately the size and weight of contemporary artillery
Artillery
Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...
pieces, and were often perceived as a replacement for cannon firing grapeshot
Grapeshot
In artillery, a grapeshot is a type of shot that is not a one solid element, but a mass of small metal balls or slugs packed tightly into a canvas bag. It was used both in land and naval warfare. When assembled, the balls resembled a cluster of grapes, hence the name...
or canister shot
Canister shot
Canister shot is a kind of anti-personnel ammunition used in cannons. It was similar to the naval grapeshot, but fired smaller and more numerous balls, which did not have to punch through the wooden hull of a ship...
. The large wheels required to move these guns around required a high firing position which increased the vulnerability of their crews. Sustained firing of gunpowder
Gunpowder
Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...
cartridges generated a cloud of smoke making concealment impossible until smokeless powder
Smokeless powder
Smokeless powder is the name given to a number of propellants used in firearms and artillery which produce negligible smoke when fired, unlike the older gunpowder which they replaced...
became available in the late 19th century. Gatling guns were targeted by artillery they could not reach and their crews were targeted by sniper
Sniper
A sniper is a marksman who shoots targets from concealed positions or distances exceeding the capabilities of regular personnel. Snipers typically have specialized training and distinct high-precision rifles....
s they could not see. The Gatling gun was used most successfully to expand European colonial empires by killing warriors of non-industrialized societies.
The Gatlings were the first widely used rapid-fire guns and, due to their multiple barrels, could offer more sustained fire than the first generation of air-cooled, recoil-operated machine guns. The weight, complexity, and resulting cost of the multibarrel design meant recoil-operated weapons, which could be made lighter and cheaper, would supplant them. Recoil-operated machine guns were light enough to be moved by one man, were easier to move through rough terrain, and could be fired from a lower, protected position. It would be another 50 years before the concept was again used to allow extremely high rates of fire, such as in minigun
Minigun
The Minigun is a 7.62 mm, multi-barrel heavy machine gun with a high rate of fire , employing Gatling-style rotating barrels with an external power source...
s, and automatic aircraft cannon.
Nordenfelt gun
The Nordenfelt Gun was a multiple barrel machine gun that had a row of up to twelve barrels. It was fired by pulling a lever back and forth. It was produced in a number of different calibres from rifle up to 25 mm...
s and Gatling guns.
Heavy guns based on the Maxim such as the Vickers machine gun
Vickers machine gun
Not to be confused with the Vickers light machine gunThe Vickers machine gun or Vickers gun is a name primarily used to refer to the water-cooled .303 inch machine gun produced by Vickers Limited, originally for the British Army...
were joined by many other machine weapons, which mostly had their start in the early 20th century such as the Hotchkiss machine gun
Hotchkiss machine gun
Hotchkiss machine gun:*Hotchkiss M1909, light machine gun also known as the "Hotchkiss Mark I" in British service*Hotchkiss M1914, medium machine gun*Hotchkiss M1922, light machine gun*13.2 mm Hotchkiss machine gun, heavy machine gun...
. Submachine gun
Submachine gun
A submachine gun is an automatic carbine, designed to fire pistol cartridges. It combines the automatic fire of a machine gun with the cartridge of a pistol. The submachine gun was invented during World War I , but the apex of its use was during World War II when millions of the weapon type were...
s (e.g., the German MP18
MP18
The MP18.1 manufactured by Theodor Bergmann Waffenbau Abteilung was the first practical submachine gun used in combat. It was introduced into service in 1918 by the German Army during World War I as the primary weapon of the Stosstruppen, assault groups specialized in trench combat...
) as well as lighter machine guns (the Chauchat
Chauchat
The Chauchat , was the standard light machine gun of the French Army during World War I. Under the leadership of General Joseph Joffre, it was commissioned into the French Army in 1916. It was also widely used by the US Army in 1917-1918 and by six other nations: Belgium, Greece, Poland, Russia,...
, for example) saw their first major use in World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
, along with heavy use of large-caliber machine guns. The biggest single cause of casualties
Casualty (person)
A casualty is a person who is the victim of an accident, injury, or trauma. The word casualties is most often used by the news media to describe deaths and injuries resulting from wars or disasters...
in World War I was actually artillery, but combined with wire entanglements, machine guns earned a fearsome reputation. The automatic mechanisms of machine guns were applied to handguns, giving rise to automatic pistols (and eventually machine pistol
Machine pistol
A machine pistol is a handgun-style, often magazine-fed and self-loading firearm, capable of fully automatic or burst fire, and normally chambered for pistol cartridges. The term is a literal translation of Maschinenpistole, the German term for a hand-held automatic weapon...
s) such as the Borchardt
Borchardt C-93
The Borchardt C-93 pistol was designed by Hugo Borchardt in 1893. Ludwig Loewe & Company of Berlin, Germany, a manufacturer of machine tools, produced the C-93, a semi-automatic pistol that he had invented based upon the Maxim toggle-lock principle. He also developed the 7.65×25mm Borchardt...
(1890s) and later submachine guns (such as the Beretta 1918). Machine guns were mounted in aircraft for the first time in World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
. Firing through a moving propeller was solved in a variety of ways, including the interrupter gear
Interrupter gear
An interrupter gear is a device used on military aircraft and warships in order to allow them to target opponents without damaging themselves....
, metal reinforcement of the propeller, or simply avoiding the problem with wing-mounted guns or having a pusher propeller.
Interwar era and World War II
During the interwar years, many new designs were developed, such as the Browning M2 .50 caliber (12.7 mm), which, along with others, were used in World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. The trend toward automatic rifles, light machine gun
Light machine gun
A light machine gun is a machine gun designed to be employed by an individual soldier, with or without an assistant, as an infantry support weapon. Light machine guns are often used as squad automatic weapons.-Characteristics:...
s, and more powerful submachine guns resulted in a wide variety of firearms that combined characteristics of ordinary rifles and machine guns. The Cei-Rigotti
Cei-Rigotti
The Cei-Rigotti is an early automatic rifle created by Amerigo Cei-Rigotti, an officer in the Italian Army, in 1890, and extensively modified until its final form circa 1900....
(20th century), Fedorov Avtomat
Fedorov Avtomat
The Fedorov Avtomat was an early assault rifle designed by Vladimir Grigoryevich Fedorov and produced in Russia in 1916. It was the first practical assault rifle to be adopted, and this concept would later become the basis for the first assault rifle to incorporate a modern layout, the StG 44...
(1910s), AVS-36 Simonov (1930s), MP44, M2 Carbine
M1 Carbine
The M1 carbine is a lightweight, easy to use semi-automatic carbine that became a standard firearm for the U.S. military during World War II, the Korean War and the Vietnam War, and was produced in several variants. It was widely used by U.S...
, AK-47
AK-47
The AK-47 is a selective-fire, gas-operated 7.62×39mm assault rifle, first developed in the Soviet Union by Mikhail Kalashnikov. It is officially known as Avtomat Kalashnikova . It is also known as a Kalashnikov, an "AK", or in Russian slang, Kalash.Design work on the AK-47 began in the last year...
, and AR-15
AR-15
The AR-15 is a lightweight, 5.56 mm, air-cooled, gas-operated, magazine-fed semi-automatic rifle, with a rotating-lock bolt, actuated by direct impingement gas operation. It is manufactured with the extensive use of aluminum alloys and synthetic materials....
have come to be known as assault rifle
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...
s (after the German term sturmgewehr). Many aircraft were equipped with machine cannon, and similar cannon (nicknamed "Pom-pom guns") were used as antiaircraft weapons. The designs of Bofors
Bofors
The name Bofors has been associated with the iron industry for more than 350 years.Located in Karlskoga, Sweden, the company originates from the hammer mill "Boofors" founded 1646. The modern corporate structure was created in 1873 with the foundation of Aktiebolaget Bofors-Gullspång...
of Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
and Oerlikon
Oerlikon Contraves
Rheinmetall Air Defence AG is a division of German armament manufacturer Rheinmetall, created when the company's Oerlikon Contraves unit was renamed on 1 January 2009 and integrated with Rheinmetall's other air-defence products...
of Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
were widely used by both sides and have greatly influenced similar weapons developed since then.
Germany developed during the interwar years the first widely used and successful general-purpose machine gun, the Maschinengewehr 34. The Maschinengewehr 42 was developed from it and was much cheaper to produce. The current GPMG of the German Army
Bundeswehr
The Bundeswehr consists of the unified armed forces of Germany and their civil administration and procurement authorities...
, the MG3, is a direct evolution of the MG42. Many other modern machine guns, including the US M60
M60 machine gun
The M60 is a family of American general-purpose machine guns firing 7.62×51mm NATO cartridges from a disintegrating belt of M13 links...
and the FN MAG
FN MAG
The FN MAG is a Belgian 7.62 mm general-purpose machine gun, designed in the early 1950s at Fabrique Nationale by Ernest Vervier. It has been used by more than 80 countries, and it has been made under licence in countries such as Argentina, Egypt, India, Singapore, the United Kingdom and the...
borrow elements of the design of the MG42.
Future
Electronically controlled machine guns with ultrahigh rates of fire may see use in some applications, although current small-caliber weapons of this type have found little use: they are too light for anti-vehicle use, but too heavy (especially with the need to carry a tactically useful amount of ammunition) for individual soldiers. The trend towards higher reliability and lower mass for a given power will probably continue. Another example is the six barreled, 4000 round per minute, XM214 "six pack" developed by General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
. It has a complex power train and weighs 85 pounds, factors which may, in some circumstances, militate against its deployment.
Human interface
The most common interface on machine guns is a pistol gripPistol grip
On a firearm or other tool, the pistol grip is that portion of the mechanism that is held by the hand and orients the hand in a forward, vertical orientation, similar to the position one would take with a conventional pistol such as the M1911....
and trigger. On earlier manual machine guns, the most common type was a hand crank. On externally powered machine guns, such as miniguns, an electronic button or trigger on a joystick is commonly used. Light machine guns often have a butt stock attached, while vehicle and tripod mounted machine guns usually have spade grips. In the late 20th century, scopes and other complex optics became more common as opposed to the more basic iron sights
Iron sights
Iron sights are a system of shaped alignment markers used as a sighting device to assist in the aiming of a device such as a firearm, crossbow, or telescope, and exclude the use of optics as in telescopic sights or reflector sights...
.
Loading systems in early manual machine guns were often from a hopper of loose (un-linked) cartridges. Manual-operated volley guns usually had to be reloaded manually all at once (each barrel reloaded by hand). With hoppers, the rounds could often be added while the weapon was firing. This gradually changed to belt-fed types. Belts were either held in the open by the person, or in a bag or box. Some modern vehicle machine guns used linkless feed systems however.
Bipod
A bipod is a support device that is similar to a tripod or monopod, but with two legs. It provides significant stability along two axes of motion .-Firearms:...
– often these are integrated with the weapon. This is common on light machine guns and some medium machine guns. Another is a tripod, where the person holding it does not form a 'leg' of support. Medium and heavy machine gun
Heavy machine gun
The heavy machine gun or HMG is a larger class of machine gun generally recognized to refer to two separate stages of machine gun development. The term was originally used to refer to the early generation of machine guns which came into widespread use in World War I...
s usually use tripods. On ships and aircraft machine guns are usually mounted on a pintle
Pintle
A pintle is a pin or bolt, usually inserted into a gudgeon, which is used as part of a pivot or hinge.A pintle/gudgeon set is used in many spheres, for example: in sailing to hold the rudder onto the boat; in transportation a pincer-type device clamps through a lunette ring on the tongue of a...
mount – basically a steel post that is connected to the frame. Tripod and pintle mounts are usually used with spade grips. The last major mounting type is one that is disconnected from humans, as part of an armament system, such as a tank coaxial or part of aircraft's armament. These are usually electrically fired and have complex sighting systems. For examples of this, see US Helicopter Armament Subsystems.
See also
- Light machine gunLight machine gunA light machine gun is a machine gun designed to be employed by an individual soldier, with or without an assistant, as an infantry support weapon. Light machine guns are often used as squad automatic weapons.-Characteristics:...
- Medium machine gunMedium machine gunA medium machine gun or MMG, in modern terms, usually refers to a belt-fed automatic firearm firing a full-power rifle cartridge.-History:...
- Heavy machine gunHeavy machine gunThe heavy machine gun or HMG is a larger class of machine gun generally recognized to refer to two separate stages of machine gun development. The term was originally used to refer to the early generation of machine guns which came into widespread use in World War I...
- Firearm actionFirearm actionIn firearms terminology, an action is the physical mechanism that manipulates cartridges and/or seals the breech. The term is also used to describe the method in which cartridges are loaded, locked, and extracted from the mechanism. Actions are generally categorized by the type of mechanism used...
- Squad automatic weaponSquad automatic weaponA squad automatic weapon is a weapon used to give infantry squads or sections a portable source of automatic firepower. Weapons used in this role are selective-fire rifles, usually fitted with a bipod and heavier barrel to perform as Light machine guns...
- Breda (machine gun)
- WeaponWeaponA weapon, arm, or armament is a tool or instrument used with the aim of causing damage or harm to living beings or artificial structures or systems...
- General-purpose machine gun
- List of firearms
- Revolver cannonRevolver cannonA revolver cannon is a type of autocannon commonly used as an aircraft gun. It uses a cylinder with multiple chambers, like those of a revolver handgun, to speed up the loading-firing-ejection cycle. Some examples are also power-driven, to further speed the loading process, but this is by no means...
- MitrailleuseMitrailleuseMitrailleuse is the French word used to describe all rapid-firing weapons of rifle caliber. Therefore the word mitrailleuse, when used in the French language, applies to all machine guns including modern full automatic weapons. However in the English language the word mitrailleuse applies to...
- The French word for machine gun, but also a type of manual volley gun. - Submachine gunSubmachine gunA submachine gun is an automatic carbine, designed to fire pistol cartridges. It combines the automatic fire of a machine gun with the cartridge of a pistol. The submachine gun was invented during World War I , but the apex of its use was during World War II when millions of the weapon type were...
- AutocannonAutocannonAn autocannon or automatic cannon is a rapid-fire projectile weapon firing a shell as opposed to the bullet fired by a machine gun. Autocannons often have a larger caliber than a machine gun . Usually, autocannons are smaller than a field gun or other artillery, and are mechanically loaded for a...
- MinigunMinigunThe Minigun is a 7.62 mm, multi-barrel heavy machine gun with a high rate of fire , employing Gatling-style rotating barrels with an external power source...
- Gatling gunGatling gunThe Gatling gun is one of the best known early rapid-fire weapons and a forerunner of the modern machine gun. It is well known for its use by the Union forces during the American Civil War in the 1860s, which was the first time it was employed in combat...
- Chain gunChain gunA chain gun is a type of machine gun or autocannon that uses an external source of power, rather than diverting energy from the cartridge, to cycle the weapon, and does so via a continuous loop of chain similar to that used on a motorcycle or bicycle. "Chain gun" is a registered trademark of...
- List of machine guns
- List of multiple barrel machine guns
External links
- GunTrustLawyer.com – US site with information on the legality of owning a machine gun in each state under the National Firearms Act and individual state regulations.
- How Stuff Works – Article on the operation of Machine Guns, animated diagrams are included. – A patent for an early automatic cannon
- Vickers machine gun site
- The REME Museum of Technology – machine guns
- Discover Military Machine Guns
- From Gatling to Browning September 1945 article Popular SciencePopular SciencePopular Science is an American monthly magazine founded in 1872 carrying articles for the general reader on science and technology subjects. Popular Science has won over 58 awards, including the ASME awards for its journalistic excellence in both 2003 and 2004...