A machine gun ( MG ) is a fully automatic and rifled firearm designed for sustained direct fire with rifle cartridges . Other automatic firearms such as automatic shotguns and automatic rifles (including assault rifles and battle rifles ) are typically designed more for firing short bursts rather than continuous firepower and are not considered true machine guns. Submachine guns fire handgun cartridges rather than rifle cartridges, therefore they are not considered machine guns, while automatic firearms of 20 mm (0.79 in) caliber or more are classified as autocannons rather than machine guns.
86-486: The Gast gun was a German twin barrelled machine gun that was developed by Karl Gast of Vorwerk und Companie of Barmen and used during the First World War . Its unique operating system produced a very high rate of fire of 1,600 rounds per minute. The same principle was later used as the basis for the widely used Gryazev-Shipunov GSh-23L series of Russian aircraft autocannon. The weapon combines two barrels into
172-486: A Portuguese fleet sent to India to take part in a colonial war in the 1740s. Also in 1737, it was mentioned that a German engineer had invented a 10-pounder cannon capable of firing 20 times in a minute. In 1740, a cannon able to shoot 11 times per minute was developed by a Frenchman called Chevalier de Benac. Meanwhile, not long after in England, in 1747 a cannon able to simultaneously charge and discharge itself 20 times in
258-411: A closed-bolt design, open-bolt weapons generally have fewer moving parts. The firing pin is often part of the bolt, saving on manufacturing costs; the inertia of the bolt closing also causes the fixed firing pin to strike a blow on the primer, without need for a separate hammer/striker and spring. In automatic weapons, an open bolt helps eliminate the dangerous phenomenon known as " cook-off ", in which
344-421: A swivel gun that did not need cleaning or muzzle-loading and was capable of being made to any dimensions and used as an ordinary cannon at a moment's notice and firing 40 shots a minute was invented by a native of Ireland. Also in 1828 a revolver cannon capable of firing 12 shots a minute and worked by 2 artillerymen was invented by a Frenchman called Lesire-Fruyer. In 1854 this cannon would be put on display at
430-516: A tripod or on a vehicle; when carried on foot, the machine gun and associated equipment (tripod, ammunition, spare barrels) require additional crew members. Light machine guns are designed to provide mobile fire support to a squad and are typically air-cooled weapons fitted with a box magazine or drum and a bipod; they may use full-size rifle rounds, but modern examples often use intermediate rounds. Medium machine guns use full-sized rifle rounds and are designed to be used from fixed positions mounted on
516-416: A French artist known as Renard invented a piece of ordnance that could be operated by one man and fired 90 shots a minute. Also in 1792, a French mechanic called Garnier invented a musket battery made up of 15 barrels capable of firing 300 shots in 2 minutes for a total rate of fire of 150 shots a minute or 10 shots per minute per barrel and of being operated by one man. In the early and mid-19th century,
602-513: A US patent in 1920, which was issued in 1923. A Gast gun was evaluated by the US Army and found to be reliable and mechanically practical. However it was not felt to offer a sufficient advantage over existing machine guns to justify the expense of producing the weapon. Years later the Gast design was copied by Soviet engineers seeking to improve firing rates of their aircraft autocannon without resorting to
688-411: A bipod and drum in the light machine gun role or a tripod and belt feed in the medium machine gun role. Machine guns usually have simple iron sights, though the use of optics is becoming more common. A common aiming system for direct fire is to alternate solid ("ball") rounds and tracer ammunition rounds (usually one tracer round for every four ball rounds), so shooters can see the trajectory and "walk"
774-407: A breech-loading volley gun , similar to the later mitrailleuse, was invented by a Frenchman called Du Perron which was worked by 3 or 4 men and capable of discharging 24 barrels 10 times a minute for a total rate of fire of 240 shots per minute. In 1776, a gun capable of charging and discharging itself 120 times 'by the motion of one hand only' in a minute was invented in England by an inventor from
860-431: A cartridge to overheat and detonate 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; this is known as cooking off (as distinct from runaway fire where the sear fails to re-engage when the trigger is released). To guard against cook-offs occurring, some kind of cooling system or design element
946-618: A common feed source. The continuous nature of the rotary action and its relative immunity to overheating allow for a very 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 in the rare cases of self-powered rotary guns. Rotary designs are intrinsically comparatively bulky and expensive and are therefore generally used with large rounds, 20 mm in diameter or more, often referred to as Rotary cannon – though
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#17330856667921032-432: A degree in closed-bolt firearms as well). Closed-bolt designs are often used in rifles . The improved accuracy of closed-bolt weapons is more desirable, while the poorer heat dissipation is less of an issue for slower-firing weapons. In contrast, open-bolt designs are more often used in automatic weapons, such as machine guns . For fast-firing automatic weapons, heat will rapidly build up from sustained firing, but accuracy
1118-437: A fixed firing pin, when the bolt is closed gently, without the momentum of the bolt closing at normal speed, there is not enough force imparted to the firing pin to ignite the primer. In this circumstance there will be a round in the chamber and a firing pin pressing on it with some force, but not enough to ignite the primer, which requires a sharp, focused impact. However, the weapon would be at risk of firing if dropped, much like
1204-443: A full-power rifle cartridge from a closed bolt are called automatic rifles or battle rifles , while rifles that fire an intermediate cartridge are called assault rifles . Assault rifles are a compromise between the size and weight of a pistol-caliber submachine gun and a full-size battle rifle, firing intermediate cartridges and allowing semi-automatic and burst or full-automatic fire options (selective fire), sometimes with both of
1290-424: A given amount of heat, while at the same time they are also much better at shedding the excess, as the extra barrels provide a larger surface area from which to dissipate the unwanted thermal energy. In addition to that, they are in the nature of the design spun at very high speed during rapid fire, which has the benefit of producing enhanced air-cooling as a side-effect. In weapons where the round seats and fires at
1376-563: A machine capable of firing 600 balls in a few minutes. In 1720, a French inventor called Philippe Vayringe invented a small cannon that could fire 16 shots in succession, which he demonstrated before the Duke of Lorraine. In 1737, it was mentioned that Jacob de Weinholtz, a Dane who was serving in the Portuguese army, had invented a cannon capable of firing 20 to 30 shots a minute though requiring 15 people to work it. The cannons were brought along with
1462-494: A machine gun is designed to continue firing for as long as the trigger is held down. Nowadays, the term is restricted to relatively heavy crew-served weapons , able to provide continuous or frequent bursts of automatic fire for as long as ammunition feeding is replete. Machine guns are used against infantry , low-flying aircraft , small boats and lightly/un armored land vehicles , and can provide suppressive fire (either directly or indirectly ) or enforce area denial over
1548-549: A minute of use. Because they become very hot, the great majority of designs fire from an open bolt , to permit air cooling from the breech between bursts. They also usually have either a barrel cooling system, slow-heating heavyweight barrel, or removable barrels which allow a hot barrel to be replaced. Although subdivided into " light ", " medium ", " heavy " or " general-purpose ", even the lightest machine guns tend to be substantially larger and heavier than standard infantry arms. Medium and heavy machine guns are either mounted on
1634-496: A minute though the rate of fire was limited by the overheating of the barrel. In 1819, an American inventor from Baltimore designed a gun with 11 barrels that could fire 12 times in a minute for a total rate of fire of 132 shots a minute. In 1821, a muzzle-loading repeating cannon capable of firing 30 shots in 6 minutes or 5 shots per minute was demonstrated in England by the French-American "Fire King" Ivan Ivanitz Chabert. It
1720-793: A minute was invented by James Allis and presented to the Royal Society of England. In 1750, in Denmark, a Prussian known as Captain Steuben of the Train of Artillery invented a breech-loading cannon worked by 4 people and fed by paper cartridges capable of firing 24 times in a minute and demonstrated it to the King of Denmark along with some other high-ranking officials in the same year. In 1764, Frenchman Ange Goudar wrote in his work The Chinese Spy that he had assisted in Paris in
1806-415: A multi-shot weapon by a Palmer during this period appear to be referring to a somewhat more common Kalthoff repeater or Lorenzoni-system gun . Despite this, there is a reference in 1663 to at least the concept of a genuine automatic gun that was presented to Prince Rupert , though its type and method of operation are unknown. In 1708, it was reported from Constantinople that a French officer had invented
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#17330856667921892-658: A number of rapid-firing weapons appeared which offered multi-shot fire, mostly volley guns. Volley guns (such as the Mitrailleuse ) and double-barreled pistols relied on duplicating all parts of the gun, though the Nock gun used the otherwise-undesirable "chain fire" phenomenon (where multiple chambers are ignited at once) to propagate a spark from a single flintlock mechanism to multiple barrels. Pepperbox pistols also did away with needing multiple hammers but used multiple manually operated barrels. Revolvers further reduced this to only needing
1978-430: A pre-prepared cylinder and linked advancing the cylinder to cocking the hammer. However, these were still manually operated. In 1805, a British inventor from Northampton designed a cannon that would prime, load and fire itself 10 times a minute. In 1806, a Viennese copper engraver and mechanic known as Mr Putz invented a machine cannon that could load, fire and clean itself once every second or potentially up to 60 times
2064-402: A reasonable rate of fire and reliability. In contrast to the rotary format, such weapons have a single barrel and a recoil-operated carriage holding 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
2150-462: A reduced rate of fire. Some designs – such as the many variants of the MG42 – are capable of rates of fire in excess of 1,200 rounds per minute. Motorized Gatling guns can achieve the fastest firing rates of all, partly because this format involves extra energy being injected into the system from outside, instead of depending on energy derived from the propellant contained within the cartridges, partly because
2236-598: A sector of land with grazing fire . They are commonly mounted on fast attack vehicles such as technicals to provide heavy mobile firepower, armored vehicles such as tanks for engaging targets too small to justify the use of the primary weaponry or too fast to effectively engage with it, and on aircraft as defensive armament or for strafing ground targets, though on fighter aircraft true machine guns have mostly been supplanted by large-caliber rotary guns. Some machine guns have in practice sustained fire almost continuously for hours; other automatic weapons overheat after less than
2322-428: A single mechanism so that the recoil from firing one barrel loads and charges the second. Ammunition feeds into the gun from two vertically mounted cylindrical drums, one on each side. The drums held 180 rounds of German 7.92 mm rifle ammunition, feeding them into the breech using a compressed spring. An experienced gunner could change ammunition drums in a few seconds. The weapon could fire single shots if one side of
2408-414: A time when close. It was also claimed to be able to shoot 5 or 6 times before infantry came within musket range or cavalry within pistol range and with no more space between each shot than the time needed to prime a pistol, cock it and release the hammer as well as being nearly as manoeuvrable as cavalry. An alternative and heavier version was said to be able to throw grenades and it was also proposed to equip
2494-492: A tripod. The heavy machine gun is a term originating in World War I to describe heavyweight medium machine guns and persisted into World War II with Japanese Hotchkiss M1914 clones; today, however, it is used to refer to automatic weapons with a caliber of at least 12.7 mm (0.5 in), but less than 20 mm (0.8 in). A general-purpose machine gun is usually a lightweight medium machine gun that can either be used with
2580-436: A very light cannon that could fire from a single barrel 30 shots in 2 and a half minutes for a total rate of fire of 12 shots a minute. In 1711, a French lawyer called Barbuot presented to the parliament of Dijon a crank-operated 'war machine' made up of 10 carbine barrels and loaded via a 'drum' capable of firing in vollies. It was said to be accurate at 400 to 500 paces and to strike with enough force to pierce 2 or 3 men at
2666-417: Is a brief delay between the trigger-pull and the firing of the cartridge because the (rather inert ) bolt has to move forward a significant distance between the two events. Since after the first shot an open-bolt firearm operates effectively indistinguishably from a closed-bolt firearm, this latency problem is generally less of a concern in full automatic fire and mostly applies to semi-automatic mode. The issue
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2752-559: Is a revolving arquebus , produced by Hans Stopler of Nuremberg in 1597. True repeating long arms were difficult to manufacture prior to the development of the unitary firearm cartridge; nevertheless, lever-action repeating rifles such as the Kalthoff repeater and Cookson repeater were made in small quantities in the 17th century. Perhaps the earliest examples of predecessors to the modern machine gun are to be found in East Asia. According to
2838-471: Is because prior to the Hughes Amendment in 1986 , most semi-automatic open bolt Mac-10s, Mac-11s, and several other models were lawfully converted to full auto making these rare semi-automatic open bolts even more desirable as collector's items. However, there are many open-bolt firearms, that were designed from start to be semi-automatic firearms and are not classified as machine guns . The Fox Carbine
2924-888: Is locked into the chamber. Almost all machine guns have a "safety" sear, which simply keeps the trigger from engaging. The first successful machine-gun designs were developed in the mid-19th century. The key characteristic of modern machine guns, their relatively high rate of fire and more importantly mechanical loading, first appeared in the Model 1862 Gatling gun , which was adopted by the United States Navy . 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; as discussed above, this externally powered machine reloading has seen use in modern weapons as well. While technical use of
3010-526: Is of less importance. Thus, the improved heat dissipation of open-bolt designs is generally more desirable in automatic weapons. Submachine guns were for much of their life designed with open bolts such as the Thompson submachine gun , MP-40 and the Uzi , mainly for the simplicity and economical advantages, and their rates of fire and close-range nature mitigated the reduced accuracy of the design. SMGs used and built in
3096-619: Is required. Early machine guns were often water-cooled and while this technology was very effective, (and was indeed one of the sources of the notorious efficiency of machine guns during the First World War ), the water jackets also added considerable weight to an already bulky design; they were also vulnerable to the enemies' bullets themselves. Armour could be provided, and in WW I the Germans in particular often did this; but this added yet more weight to
3182-543: Is the recoil actuated type, which uses the gun's recoil energy for the same purpose. Machine guns, such as the M2 Browning and MG42 , are of this second kind. A cam, lever or actuator absorbs part of the energy of the recoil to operate the gun mechanism. An externally actuated weapon uses an external power source, such as an electric motor or hand crank, to move its mechanism through the firing sequence. Modern weapons of this type are often referred to as Gatling guns , after
3268-515: Is thus only exposed to the residual heat for a fraction of a second. These two features combine to make open-bolt operation more suitable for weapons such as machine guns , which are intended to be capable of prolonged automatic fire. Open-bolt firearms also allow water drainage in underwater firearms . Firstly, the bolt retention mechanism may fail, resulting in a spontaneous discharge (i.e. without prior trigger input), with potentially dangerous consequences. Some simple submachine gun designs, such as
3354-405: Is used, breech and action internals' exposure to the elements renders open-bolt designs universally vulnerable to contamination with dirt and dust through the open ejection port. Some versions of the open-bolt M3 submachine gun utilize a hinged sheet metal ejection port cover that doubles as a safety; when closed, it both covers the ejection port and blocks the bolt from closing. When ready to fire,
3440-709: The 2K22 Tunguska and Pantsir S1 . Machine gun As a class of military kinetic projectile weapons, machine guns are designed to be mainly used as infantry support weapons and generally used when attached to a bipod or tripod , a fixed mount or a heavy weapons platform for stability against recoils . Many machine guns also use belt feeding and open bolt operation, features not normally found on other infantry firearms. Machine guns can be further categorized as light machine guns , medium machine guns , heavy machine guns , general-purpose machine guns , and squad automatic weapons . Unlike semi-automatic firearms , which require one trigger pull per round fired,
3526-607: The Gatling gun concept or powered revolver cannon . Previous efforts either had relatively poor rates of fire, or used gas operated revolvers, neither of which proved entirely satisfactory. The Gast concept was adopted for the Gryazev-Shipunov GSh-23 , which quickly replaced many previous designs. It was also used in the larger 30 mm version, the Gryazev-Shipunov GSh-30-2 , as well as the 2A38 autocannon found on
Gast gun - Misplaced Pages Continue
3612-456: The Nordenfelt gun . The first known ancestors of multi-shot weapons were medieval organ guns . An early example of an attempt at the mechanisation of one of these would be an 'engine of war' produced in the mid-1570s in England capable of firing from 160 to 320 shots 4, 8, 12 or 24 bullets at a time at a rate of fire up to roughly 3 times the rate of fire of the typical arquebusier of the day. It
3698-445: The Sten , can discharge spontaneously when dropped onto a hard surface – even when uncocked – as the collision can jolt the bolt backward far enough that on returning it will pick up a round from the magazine, chamber it and fire it; the risk is intrinsic to hand-held open-bolt guns unless safety features are included in the design. Another shortcoming of the open-bolt principle is that there
3784-574: The French Museum of the Marine. In France, in 1831, a mechanic from the Vosges department invented a lever-operated cannon that could fire 100 shots a minute. In 1832, a machine capable of firing 500 rifle shots a minute was devised by Hamel, a French mechanic. Open bolt A firearm is said to fire from an open bolt or open breech if, when ready to fire, the bolt and working parts are held to
3870-670: The Gast-Flieger MG, was also under development, which used the same ammunition as the Maxim MG TuF and had two, curved, box magazines. The gun was rarely used in service, and its existence was kept secret until three years after the Armistice ; in 1921 the Allied Control Commission finally became aware of the Gast gun when a cache of 25 of the guns, ammunition, and designs was found near Königsberg . Gast himself had applied for
3956-552: The Vorwerk company, the first weapon was produced in January 1916. Gast took out patents on 21 January 1916 and 13 February 1917, describing his weapon as "a double-barreled machine gun with recoiling barrels". Rates of fire of 1,600 rounds per minute were achieved during trials. In August 1917, Gast's demonstration so impressed ordnance experts that a production order for 3,000 guns, along with spare parts and ten ammunition drums for each gun,
4042-658: The Wu-Pei-Chih, a booklet examining Chinese military equipment produced during the first quarter of the 17th century, the Chinese army had in its arsenal the 'Po-Tzu Lien-Chu-P'ao' or 'string-of-100-bullets cannon'. This was a repeating cannon fed by a hopper containing balls which fired its charges sequentially. The way it worked was similar to the Perkins steam gun of 1824 or the Beningfield electrolysis gun of 1845 only slow-burning gunpowder
4128-461: The basis of size; those using shotgun cartridges are almost always referred to as automatic shotguns . The term personal defense weapon (PDW) is sometimes applied to weapons firing dedicated armor-piercing rounds which would otherwise be regarded as machine pistols or SMGs, but it is not particularly strongly defined and has historically been used to describe a range of weapons from ordinary SMGs to compact assault rifles. Selective-fire rifles firing
4214-433: The bolt to the closed position), as soon as the bolt closes it will fire if a loaded magazine was left in the gun. This may be true with weapons utilizing a striker , but not with a weapon using a fixed firing pin , which relies on the momentum of the bolt to impart the energy to ignite the primer . This is a common feature in basic submachine guns like the Sten gun or M3 "Grease Gun" , and even some machine guns . With
4300-406: 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. A Chain gun is a specific, patented type of Revolver cannon, the name, in this case, deriving from its driving mechanism. As noted above, firing a machine gun for prolonged periods produces large amounts of heat. In a worst-case scenario, this may cause
4386-538: The county of Westmoreland. In 1777, Philadelphia gunsmith Joseph Belton offered the Continental Congress a "new improved gun" , which was capable of firing up to twenty shots in five seconds; unlike older repeaters using complex lever-action mechanisms, it used a simpler system of superposed loads , and was loaded with a single large paper cartridge . Congress requested that Belton modify 100 flintlock muskets to fire eight shots in this manner, but rescinded
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#17330856667924472-663: The current day, such as the H&K MP5 series , have almost universally moved to closed-bolt designs for their practical advantages. Examples of mixed mode firearms (capable of operating from either an open bolt or closed bolt) include: Under United States federal law, fully automatic firearms are restricted under the National Firearms Act and other laws. In 1982, the Bureau of Alcohol, Tobacco, Firearms and Explosives ruled that certain semi-automatic open-bolt firearms manufactured after
4558-402: The danger of loading spitzer bullets into a weapon with a tube magazine . A related issue is that the safety of an open-bolt weapon must be designed to lock the bolt in the rearward position. Often safeties only block the movement of the trigger, so, as explained above, if the weapon is dropped or if the sear becomes worn, the bolt can slam home, firing the weapon (although this issue is true to
4644-638: The date of the rulings are to be treated as fully automatic because they were "designed to shoot" automatically. The aforementioned weapons are the KG-9 pistol, SM-10 pistol, SM-11A pistol, SAC Carbine, and the YAC Sten MK II. Around the time of these rulings, the manufacture of new open-bolt semi-automatic firearms became uncommon in the United States. The open bolt semi-automatic versions of certain guns are often as costly as their fully automatic counterparts. This
4730-519: The fire into the target, and direct the fire of other soldiers . Many heavy machine guns , such as the Browning M2 .50 BMG machine gun, are accurate enough to engage targets at great distances. During the Vietnam War , Carlos Hathcock set the record for a long-distance shot at 7,382 ft (2,250 m) with a .50 caliber heavy machine gun he had equipped with a telescopic sight . This led to
4816-419: The firing chamber becomes so hot that rounds spontaneously fire without trigger input. Open-bolt designs typically remain much cooler in operation than closed-bolt types due to the airflow allowed into the chamber, action and barrel during pauses between bursts; moreover, unlike in the case of the closed-bolt format, the initial round in a burst is not introduced into the chamber until the moment before firing, and
4902-568: The guns. Air-cooled machine guns often feature quick-change barrels (often carried by a crew member), passive cooling fins, or in some designs forced-air cooling, such as that employed by the Lewis Gun . Advances in metallurgy and the use of special composites in barrel liners have allowed for greater heat absorption and dissipation during firing. 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
4988-507: The introduction of .50 caliber anti-materiel sniper rifles , such as the Barrett M82 . Other automatic weapons are subdivided into several categories based on the size of the bullet used, whether the cartridge is fired from a closed bolt or an open bolt , and whether the action used is locked or is some form of blowback . Fully automatic firearms using pistol-caliber ammunition are called machine pistols or submachine guns largely on
5074-591: The inventions mentioned in the book, it is uncertain if it was ever built. It is sometimes claimed (i.e. in George Morgan Chinn's the Machine Gun ) that in 1663 the first mention of the automatic principle of machine guns was in a paper presented to the Royal Society of England by Palmer, an Englishman who described a volley gun capable of being operated by either recoil or gas. However, no one has been able to find this paper in recent times and all references to
5160-524: The latter presents. Many machine guns are of the locked breech type, and follow this cycle: The operation is basically the same for all locked breech automatic firearms, regardless of the means of activating these mechanisms. There are also multi-chambered formats, such as revolver cannon , and some types, such as the Schwarzlose machine gun etc., that do not lock the breech but instead use some type of delayed blowback . Most modern machine guns are of
5246-510: The locking type, and of these, most utilize the principle of gas-operated reloading , which taps off some of the propellant gas from the fired cartridge, using its mechanical pressure to unlock the bolt and cycle the action. The first of these was invented by the French brothers Claire, who patented a gas operated rifle, which included a gas cylinder, in 1892. The Russian PK machine gun is a more modern example. Another efficient and widely used format
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#17330856667925332-438: The machine with a bellows for clearing smoke that built up during firing. Another early revolving gun was created by James Puckle , a London lawyer, who patented what he called "The Puckle Gun " on May 15, 1718. It was a design for a manually operated 1.25 in. (32 mm) caliber, flintlock cannon with a revolver cylinder able to fire 6–11 rounds before reloading by swapping out the cylinder, intended for use on ships . It
5418-492: The mechanism had a problem. The gun's relative lightness at approximately 27 kg (60 lb) without ammunition led to its airborne use; a telescopic sight was mounted between the two barrels. Its simple design eased maintenance and enabled it to be field stripped in one minute. In January 1915, Karl Gast invented the gun, which would become known as the Gast Maschinengewehr Modell 1917 , while working for
5504-435: The movement of the heavy bolt mass within the gun negatively affects aim and accuracy in two ways: While the latency is unavoidable with the open-bolt design, more sophisticated delayed-blowback open-bolt designs do allow for use of a lighter bolt, thus reducing the gap in performance between open and closed bolt types. However, these designs are uncommon due to economics and complexity. Lastly, unless an ejection port cover
5590-430: The next round can be inserted simultaneously with or before the ejection of the previous cartridge case, and partly because this design intrinsically deals with the unwanted heat very efficiently – effectively quick-changing the barrel and chamber after every shot. The multiple guns that comprise a Gatling being a much larger bulk of metal than other, single-barreled guns, they are thus much slower to rise in temperature for
5676-628: The next round. In an open-bolt gun firing semi-automatically, the bolt is caught and held at this point by the sear after each shot; and in automatic open-bolt fire, it's caught and held in this manner whenever the trigger is released. In contrast to this, in closed-bolt guns, the trigger and sear do not affect the movement of the bolt directly. Generally, an open-bolt firing cycle is used for fully automatic weapons and not for semi-automatic weapons (except some semi-automatic conversions of automatic designs). Firearms using advanced primer ignition blowback inherently fire from open bolt only. Compared to
5762-413: The order when Belton's price proved too high. In 1779, a machine made up of 21 musket barrels worked by 3 men was produced by a British inventor called William Wilson Wright which he claimed could be fired 3 times quicker than a single man could load and fire a musket 3 times. In 1788, a Swiss soldier invented a machine worked by 10 men capable of discharging 300 balls in 3 minutes. Also in 1788, it
5848-413: The original inventor (not only of the well-known hand-cranked 19th century proto-machine gun, but also of the first electrically powered version). They have several barrels each with an associated chamber and action on a rotating carousel and a system of cams that load, cock, and fire each mechanism progressively as it rotates through the sequence; essentially each barrel is a separate bolt-action rifle using
5934-408: The proofing of a 'great gun' capable of firing 60 times in a minute. In 1773, another cannon capable of firing 23 or 24 times in a minute and cleaning itself after every shot was invented by Thomas Desaguliers . In 1775, it was mentioned that in England two large cannons invented by an unidentified matross at Woolwich had achieved a rate of fire of 59 shots in 59 and a half seconds. Also in 1775,
6020-400: The propeller blades difficult and often requiring extensive modification (but not impossible). Furthermore, with unlocked simple blowback action designs, calibers over 9×19mm Parabellum become increasingly less practical because of the need for correspondingly heavier bolts as the chamber pressure increases. In simple blowback open-bolt designs, even in such relatively low-power calibers,
6106-417: The rear of the receiver, with no round in the chamber. When the trigger is actuated, the bolt travels forward, feeds a cartridge from the magazine or belt into the chamber , and fires that cartridge in the same movement. Like any other self-loading design, the action is cycled by the energy released from the propellant, which sends the bolt back to the rear, compressing the mainspring in readiness for firing
6192-521: The rifle-calibre Minigun is an exception to this. Whereas such weapons are highly reliable and formidably effective, one drawback is that the weight and size of the power source and driving mechanism makes them usually impractical for use outside of a vehicle or aircraft mount. Revolver cannons , such as the Mauser MK 213 , were developed in World War II by the Germans to provide high-caliber cannons with
6278-406: 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
6364-408: The situation. For handheld weapons, typically a lower rate of fire is desirable, as this will conserve ammunition and help keep the level of recoil more manageable. For vehicle-mounted weapons or fixed emplacements, however, a higher rate of fire is often desirable. In these situations, ammunition and recoil are less of a concern and the higher rate of fire will increase the likelihood of a round hitting
6450-401: The target, particularly when employed against fast-moving targets such as aircraft. Many movies and video games portray open-bolt weapons as needing to be cycled after reloading. This is not generally true, however, as open-bolt weapons send the bolt carrier back into a cocked position via the excess gas after the last round is fired. The exception to this is if the weapon is fully automatic and
6536-538: The term "machine gun" has varied, the modern definition used by the Sporting Arms and Ammunition Manufacturers' Institute of America is "a fully automatic firearm that loads, fires and ejects continuously when the trigger is held to the rear until the ammunition is exhausted or pressure on the trigger is released." This definition excludes most early manually operated repeating arms the Gatling gun and such as volley guns like
6622-430: The trigger is held down after the last round was fired (and the gun does not have a "last round bolt hold open" mechanism) at which point the bolt will fly forward once more and stay there. In this case, the bolt merely needs to be retracted to the rearward position and does not return forward as is sometimes portrayed. Another feature of open-bolt designs is that the magazine simply needs to be removed to completely unload
6708-454: The user simply flips the cover down, opening the ejection port and unblocking the bolt. An open-bolt weapon will typically have a higher rate of automatic fire than a comparable closed-bolt weapon as the bolt simply needs to return forwards in order for the weapon to fire again, while a closed-bolt design has the additional step of the hammer striking the firing pin. Having a higher fire rate can be both an advantage and disadvantage depending on
6794-414: The weapon. A closed bolt requires the second step of cycling the action to remove the last round in the chamber (unless the weapon features an automatic hold-open device). It is essential to remove a loaded magazine before performing maintenance, or trying to cycle or close the bolt (as is often done to keep the weapon clean when not in use). If one were to close the bolt (say by pulling the trigger and riding
6880-662: Was also claimed that the gun could be reloaded 'as often as you like' and fired no matter the weather though the English government never adopted the weapon despite testing being carried out at the Tower of London . The first firearms to have the ability to fire multiple shots from a single barrel without a full manual reload were revolvers made in Europe in the late 1500s. One is a shoulder-gun-length weapon made in Nuremberg, Germany, circa 1580. Another
6966-489: Was awarded to Vorwerk und Companie at a unit price of 6,800 marks each. Delivery of the first 100 guns was promised for 1 June 1918, with production increasing to 500 guns per month by September 1918. Production of the weapon exceeded these initial projections, and the weapons were favorably received with promises of an order for a further 6,000 guns being made in September 1918. A version of the gun in 13 mm ( 13.2×92mmSR ),
7052-492: Was most problematic in the use of forward-firing open-bolt machine guns and autocannons in ( tractor configuration single-engine) fighters during the piston engine era. Given the highly dynamic nature of aerial combat, the aforementioned intrinsic firing delay of open-bolt guns is particularly undesirable. The inertia and latency inherent to the open bolt design negatively affects predictability and control and makes fitting open-bolt designs with synchronization gear to fire through
7138-455: Was one of the earliest weapons to be referred to as a machine gun, being called such in 1722, though its operation does not match the modern usage of the term. According to Puckle, it was able to fire round bullets at Christians and square bullets at Turks . However, it was a commercial failure and was not adopted or produced in any meaningful quantity. In 1729, a report was written in France on
7224-413: Was reported that a Prussian officer had invented a gun capable of firing 400 balls one after the other. In 1790, a former officer in the French military known as Joseph-François-Louis Grobert invented a 'ballistic machine' or 'pyroballistic machine' with multiple barrels operated by 4 men and a continuous rotational movement capable of firing 360 rifle shots a minute in a variety of calibers. In 1792,
7310-556: Was used as the propelling force in place of steam or the gases produced by electrolysis. Another repeating gun was produced by a Chinese commoner, Dai Zi, in the late 17th century. This weapon was also hopper-fed and never went into mass production. In 1655, a way of loading, aiming and shooting up to 6 wall muskets 60 times in a minute for a total rate of fire of 360 shots per minute was mentioned in The Century of Inventions by Edward Somerset, 2nd Marquess of Worcester , though, like all
7396-420: Was worked by a "wheel" fed by paper cartridges from a store attached to the cannon and ignited using a match from a match-holder somewhere else on the cannon. In 1825 an Italian book attempting to catalogue all topographic features of all known countries on Earth mentioned that in France there were 'mechanical rifles' used to defend warehouses that were capable of firing 120 shots without reloading. In 1828,
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