Misplaced Pages

#27972

48-455: The XM312 is a heavy machine gun derived from the XM307 25 mm autocannon and chambered for the .50 BMG cartridge. It was designed in response to a request by the U.S. military for a replacement for the aging M2 Browning heavy machine gun, and as a complement to the heavier XM307 Advanced Crew Served Weapon grenade launcher. It is capable of being converted quickly into an XM307 with

96-553: A bipod in the light machine gun role or on a tripod or other weapon mount as medium machine guns. An example was the Hotchkiss M1909 machine gun weighing 27.6 lb (12.2 kg) fitted with a mini-tripod and using linkable 30-round ammunition strips, but there was also a belt-fed version. This type of multipurpose machine gun would be further developed, and later given names such as "universal machine gun", and later "general-purpose machine gun", and would eventually supplant

144-411: A machine gun . Autocannons have a longer effective range and greater terminal performance than machine guns, due to the use of larger/heavier munitions (most often in the range of 20–60 mm (0.79–2.36 in), but bigger calibers also exist), but are usually smaller than tank guns , howitzers , field guns , or other artillery . When used on its own, the word "autocannon" typically indicates

192-491: A 24-inch barrel. A famous photo of Maxim showed him picking it up by its 15-pound tripod (6.8 kg) with one arm. It was similar to present-day medium machine guns, but it could not be fired for extended periods due to overheating. As a result, Maxim created a water jacket cooling system to enable it to fire for extended periods. However, this added significant weight, as did the change to more powerful rifle cartridges. There were thus two main types of heavy, rapid-fire weapons:

240-598: A consequence, fighters at the time had cannons added back in external "gun pods", and virtually all fighter aircraft retain autocannons in integral internal mounts to this day. After the Second World War, autocannons continued to serve as a versatile weapon in land, sea, and air applications. Examples of modern autocannons include the 25 mm Oerlikon KBA mounted on the IFV Freccia , the M242 Bushmaster mounted on

288-586: A modern autocannon ranges from 90 rounds per minute , in the case of the British RARDEN, to 2,500 rounds per minute with the GIAT 30 . Rotary systems with multiple barrels can achieve over 10,000 rounds per minute (the Russian GSh-6-23 , for example). Such extremely high rates of fire are effectively employed by aircraft in aerial dogfights and close air support on ground targets via strafing attacks, where

336-625: A non-rotary weapon with a single barrel . When multiple rotating barrels are involved, such a weapon is referred to as a "rotary autocannon" or occasionally " rotary cannon ", for short (particularly on aircraft). Autocannons are heavy weapons that are unsuitable for use by infantry . Due to the heavy weight and recoil , they are typically installed on fixed mounts , wheeled carriages , ground combat vehicles , aircraft , or watercraft , and are almost always crew-served , or even remote-operated with automatic target recognition / acquisition (e.g. sentry guns and naval CIWS ). As such, ammunition

384-465: A rate of over 200 rounds a minute: much faster than conventional artillery while possessing a much longer range and more firepower than the infantry rifle . In 1913, Reinhold Becker and his Stahlwerke Becker firm designed the 20mm Becker cannon , addressing the German Empire 's perceived need for heavy-calibre aircraft armament. The Imperial Government's Spandau Arsenal assisted them in perfecting

432-492: A role to which they were suited as tank armour is often lightest on top. The Polish 20 mm 38 Fk auto cannon was expensive to produce, but an exception. Unlike the Oerlikon, it was effective against all the tanks fielded in 1939, largely because it was built as an upgrade to the Oerlikon, Hispano-Suiza, and Madsen. It even proved capable of knocking out early Panzer IIIs and IVs, albeit with great difficulty. Only 55 were produced by

480-524: A short period of time. The development of guided missiles was thought to render cannons unnecessary and a full generation of western fighter aircraft was built without them. In contrast, all Eastern Bloc aircraft kept their guns. During the Vietnam War , however, the United States Air Force realized that cannons were useful for firing warning shots and for attacking targets that did not warrant

528-407: A single cannon shell with a high-explosive payload could instantly sever essential structural elements, penetrate armour or open up a fuel tank beyond the capacity of self-sealing compounds to counter, even from fairly long range. (Instead of explosives, such shells could carry incendiaries, also highly effective at destroying planes, or a combination of explosives and incendiaries.) Thus by the end of

SECTION 10

#1732876616028

576-554: A small number of parts and a few minutes of work at the unit level (and vice versa from the XM307). The Fiscal Year 2008 Appropriations bill awarded $ 10 million to General Dynamics for the XM307 and XM312. In May 2008 the U.S. Army had awarded General Dynamics Armament and Technical Products (GDATP) a $ 9 million contract to develop a lightweight .50-caliber machine gun called the XM806 to supplement

624-509: A very effective tactic in vehicle-centered warfare, and the significantly lighter air-cooled designs could nearly match the capabilities of the water-cooled versions. Gatling -type machine guns such as the Minigun and GShG-7.62 reappeared after World War II. These are typically mounted on ships and helicopters because of their weight and large ammunition requirements due to their extremely high rate of fire. The need for sustained automatic fire on

672-411: A well-trained crew could fire nonstop for hours, given sufficient ammunition, replacement barrels and cooling water. Carefully positioned HMGs could stop an attacking force before they reached their objectives. However, during the same period a number of lighter and more portable air-cooled designs were developed weighing less than 30 lbs (15 kg). In World War I they were to be as important as

720-407: Is regarded as the archetypal modern revolver cannon . With multiple chambers and a single barrel, autocannons using the revolver principle can combine a very high rate of fire and high acceleration to its maximum firing rate with low weight, at cost of a reduced sustained rate of fire compared to rotary cannon. They are therefore used mainly in aircraft for AA purposes, in which a target is visible for

768-458: Is typically fed from a belt system to reduce reloading pauses or for a faster rate of fire , but magazines remain an option. Common types of ammunition, among a wide variety, include HEIAP , HEDP and more specialised armour-piercing (AP) munitions, mainly composite rigid ( APCR ) and discarding sabot ( APDS ) rounds. Capable of generating extremely rapid firepower , autocannons overheat quickly if used for sustained fire, and are limited by

816-400: The 7.92×57mm Mauser , 7.7×56mmR (.303 British) or 7.62×54mmR , but featured heavy construction, elaborate mountings and water-cooling mechanisms that enabled long-range sustained automatic fire with excellent accuracy. However, these advantages came at the cost of being too cumbersome to move and required a crew of several soldiers to operate them. Thus, in this sense, the "heavy" aspect of

864-400: The German Empire 's 13.2×92mmSR caliber MG 18 TuF ( Maschinengewehr 18 Tank und Flieger , 'Machinegun 18 Tank and Aircraft') during World War I , these weapons are designed to provide increased range, penetration and destructive power against vehicles, buildings, aircraft and light fortifications beyond the standard rifle calibers used in medium or general-purpose machine gun, or

912-638: The MG 08 and the Vickers, as well as the American M1917 Browning machine gun , were all substantial weapons. The .303 Vickers, for example, weighed 33 lb (15 kg) and was mounted on a tripod that brought the total weight to 50 lb (23 kg). The heavier designs could, and in some cases did, fire for days on end, mainly in fixed defensive positions to repel infantry attacks. These machine guns were typically mounted on tripods and were water-cooled, and

960-562: The Messerschmitt 410 Hornisse (Hornet) bomber destroyer. 300 examples of the BK 5 cannon were built, more than all other versions. The PaK 40 semi-automatic 7.5 cm calibre anti-tank gun was the basis for the BK 7,5 in the Junkers Ju 88 P-1 heavy fighter and Henschel Hs 129 B-3 twin engined ground attack aircraft. The German Mauser MK 213 was developed at the end of the Second World War and

1008-451: The Nordenfelt gun and Gardner gun were often made in a variety of calibers, such as 0.5-inch and 1-inch. Due to their multiple barrels, overheating was not so much of an issue, but they were also quite heavy. When Maxim developed his recoil-powered Maxim gun using a single barrel, his first main design weighed a modest 26 pounds (11.8 kg) and fired a .45-inch rifle-caliber bullet from

SECTION 20

#1732876616028

1056-629: The Oerlikon 20 mm , the Bofors 40 mm and various German Rheinmetall autocannons would see widespread use by both sides during the Second World War; not only in an anti-aircraft role, but as a weapon for use against ground targets as well. Heavier anti-aircraft cannon had difficulty tracking fast-moving aircraft and were unable to accurately judge altitude or distance, while machine guns possessed insufficient range and firepower to bring down aircraft consistently. Continued ineffectiveness against aircraft despite

1104-507: The Vickers , and Russia with the PM M1910 ). The modern definition refers to a class of machine guns chambered in "heavy caliber" ammunition, generally with a minimum bullet diameter of 12mm, a minimum cartridge case length of 80mm and a minimum bullet weight of 500 grain , but below a bullet diameter of 20mm which are considered "medium caliber" ammunition for autocannons . Pioneered by

1152-586: The ZB vz. 30 , the Bren , the MG34 and the MG42 . The heavier designs continued to be used throughout World War II and into the 1960s, but were gradually phased out in favor of air-cooled designs. The mediums were now used both as medium machine guns while mounted on tripods and as light machine guns while mounted on bipods. This was possible in part because a heavy, static MG position was not

1200-497: The Browning M2. The XM806 was canceled in 2012. The Army at present will continue buying new M2s and Mk 19s to replenish the current guns that are wearing out. Heavy machine gun There are two classes of weapons generally defined as HMGs: The term originally referred to the generation of machine guns which came to prominence in the lead up to and during World War I . These fired standard full-power rifle cartridges such as

1248-509: The amount of ammunition that can be carried by the weapons systems mounting them. Both the US 25 mm M242 Bushmaster and the British 30 mm RARDEN have relatively slow rates of fire so as not to deplete ammunition too quickly. The Oerlikon KBA 25 mm has a relatively mid-high rate of fire 650 rounds per minute but can be electronically programmed to 175-200 rounds per minute. The rate of fire of

1296-553: The earlier phases of the war, the Japanese aircraft they dealt with were not only unusually lightly built but went without either armour plate or self-sealing tanks in order to reduce their weight. Nevertheless, the U.S. also adopted planes fitted with autocannon, such as the Lockheed P-38 Lightning, despite experiencing technical difficulties with developing and manufacturing these large-calibre automatic guns. Weapons such as

1344-412: The end of 1915 , almost entirely replaced wood and fabric biplanes . At the same time as they began to be made from stronger materials, the machines also increased in speed, streamlining, power and size, and it began to be apparent that correspondingly more powerful weapons would be needed to counter them. Conversely, they were becoming much better able to carry exactly such larger and more powerful guns;

1392-464: The expenditure of a (much more expensive) missile, and, more importantly, as an additional weapon if the aircraft had expended all its missiles or enemy aircraft were inside of the missiles' minimum target acquisition range in a high-G close range engagement. This was particularly important with the lower reliability of early air-to-air missile technology, such as that employed during the Vietnam War. As

1440-576: The fuselage or wings. The 37 mm BK 3,7 cannon, based on the German Army's 3.7 cm FlaK 43 anti-aircraft autocannon was mounted in pairs in underwing gun pods on a small number of specialized Stuka Panzerknacker (tank buster) aircraft. The BK 5 cm cannon , based on the 5 cm KwK 39 cannon of the Panzer III , was installed in Ju 88P bomber destroyers , which also used other Bordkanone models, and in

1488-411: The ground, however, is now nearly entirely filled by air-cooled medium machine guns. Autocannon An autocannon , automatic cannon or machine cannon is a fully automatic gun that is capable of rapid-firing large- caliber (20 mm/0.79 in or more) armour-piercing , explosive or incendiary shells , as opposed to the smaller-caliber kinetic projectiles ( bullets ) fired by

XM312 - Misplaced Pages Continue

1536-483: The guns in aircraft failed, as the weight severely limited both speed and altitude, thus making successful interception impossible. The more effective QF 2 pounder naval gun would be developed during the war to serve as an anti-aircraft and close range defensive weapon for naval vessels. Autocannons would serve to a much greater extent and effect during the Second World War . The German Panzer II light tank, which

1584-627: The heavier designs, and were used to support infantry on the attack, on aircraft, and on many types of vehicles. The lightest of the new designs were not capable of sustained automatic fire, as they did not have water jackets and were fed from comparatively small magazines . Essentially machine rifles with a bipod , weapons like the Lewis Gun , Chauchat and the Madsen were portable by one soldier, but were made for single and burst fire. The medium designs offered greater flexibility, either being fitted with

1632-445: The intermediate cartridges used in light machine guns. In this sense, the "heavy" aspect of the weapon refers to its superior power and range over light and medium caliber weapons, in addition to its weight. This class of machine gun came into widespread use during World War II , when the M2 was used widely in fortifications, on vehicles and in aircraft by American forces. A similar HMG capacity

1680-427: The introduction of self sealing fuel tanks provided reliable protection against these small projectiles. These new defenses, synergistically with the general robustness of new aircraft designs and of course their sheer speed, which made simply shooting them accurately in the first place far more difficult, entailed that it took a lot of such bullets and a fair amount of luck to cause them critical damage; but potentially

1728-466: The large numbers installed during the second World War led, in the West, to the removal of almost all shipboard anti-aircraft weapons in the early post-war period. This was only reversed with the introduction of computer-controlled systems. The German Luftwaffe deployed small numbers of the experimental Bordkanone series of heavy aircraft cannon in 37, 50 and 75 mm calibres, mounted in gun pods under

1776-611: The manually powered, multiple-barrel machine guns and the single-barrel Maxim guns. By the end of the 19th century, many new designs such as the M1895 Colt–Browning and Hotchkiss M1897 were developed, powered by gas operation or recoil operation . Also, rather than the heavy water jacket, new designs introduced other types of barrel cooling, such as barrel replacement, metal fins, heat sinks or some combination of these. Machine guns diverged into heavier and lighter designs. The later model water-cooled Maxim guns and its derivatives

1824-569: The ordnance. Although only about 500+ examples of the original Becker design were made during World War I, the design's patent was acquired by the Swiss Oerlikon Contraves firm in 1924, with the Third Reich's Ikaria-Werke firm of Berlin using Oerlikon design patents in creating the MG FF wingmount cannon ordnance. The Imperial Japanese Navy 's Type 99 cannon , adopted and produced in 1939,

1872-554: The target dwell time is short and weapons are typically operated in brief bursts. The first modern autocannon was the British QF 1-pounder , also known as the "pom-pom". This was essentially an enlarged version of the Maxim gun , which was the first successful fully automatic machine gun, requiring no outside stimulus in its firing cycle other than holding the trigger. The pom-pom fired 1 pound (0.45 kg) gunpowder-filled explosive shells at

1920-451: The technology of which was in the meantime also developing, providing significantly improved rates of fire and reliability. When the Second World War did break out, it was swiftly realised that the power of contemporary aircraft allowed armour plate to be fitted to protect the pilot and other vulnerable areas. This innovation proved highly effective against rifle-calibre machine gun rounds, which tended to ricochet off harmlessly. Similarly

1968-616: The time of the Polish Defensive War. However it was in the air war that these weapons played their most important part in the conflict. During the First World War, rifle-calibre machine guns became the standard weapons of military aircraft. In the Second, several factors brought about their replacement by autocannon. During the inter-war years, aircraft underwent extensive evolution and the all-metal monoplane , pioneered as far back as

XM312 - Misplaced Pages Continue

2016-655: The war, the fighter aircraft of almost all the belligerents mounted cannon of some sort, the only exception being the United States which in most cases favoured the Browning AN/M2 "light-barrel" .50 calibre heavy machine gun . A fighter equipped with these intermediate weapons in sufficient numbers was adequately armed to fulfill most of the Americans' combat needs aloft, as they tended to confront enemy fighters and other small planes far more often than large bombers; and as, in

2064-471: The water-cooled designs. These later designs used quick-change barrel replacement to reduce overheating, which further reduced the weapon's weight, but at the cost of increasing the soldier's load due to the extra barrels. Some earlier designs like the Vickers had this feature, but it was mainly for barrel wear, as they normally used water cooling. It was in the 1920s and 1930s that quick barrel replacement for cooling purposes became more popular in weapons such as

2112-450: The weapon referred to the weapon's bulk and ability to sustain fire, not the cartridge caliber. This class of weapons was best exemplified by the Maxim gun , invented by the American inventor Hiram Maxim . The Maxim was the most ubiquitous machine gun of World War I, variants of which were fielded in large simultaneously by three separate warring nations—Germany with the MG 08 , Britain with

2160-410: The widespread adoption and modernization of the class, and most nations' armed forces are equipped with some type of HMG. Currently, machine guns with calibers smaller than 10mm are generally considered medium or light machine guns, while those larger than 15mm are generally classified as autocannons instead of HMGs. In the late 19th century, Gatling guns and other externally powered types such as

2208-719: Was also based on the Becker/Oerlikon design's principles. During the First World War , autocannons were mostly used in the trenches as anti-aircraft guns . The British used pom-pom guns as part of their air defences to counter the German Zeppelin airships that made regular bombing raids on London . However, they were of little value, as their shells neither ignited the hydrogen of the Zeppelins nor caused sufficient loss of gas (and hence lift) to bring them down. Attempts to use

2256-594: Was later fielded by the Soviets in the form of Vasily Degtyaryov's DShK in 12.7×108mm . The ubiquitous German MG42 general-purpose machine gun, though well-suited against infantry, lacked the M2's anti-fortification and anti-vehicle capability, a fact that was noted and lamented by the Germans. The continued need for a longer-range machine gun with anti-materiel capability to bridge the gap between exclusively anti-infantry weapons and exclusively anti-materiel weapons has led to

2304-580: Was one of the most numerous in German service during the invasion of Poland and the campaign in France , used a 20 mm autocannon as its main armament. Although ineffective against tank armour even during the early years of the war, the cannon was effective against light-skinned vehicles as well as infantry and was also used by armoured cars . Larger examples, such as the 40 mm Vickers S , were mounted in ground attack aircraft to serve as an anti-tank weapon,

#27972