This article includes a list of general references, but it remains largely unverified because it lacks sufficient corresponding inline citations . (December 2009) (Learn how and when to remove this template message)
|A-12.7 aircraft machine gun|
|Type||Single-barrel aircraft machine gun|
|Place of origin||Soviet Union|
|Used by||Soviet Union, Russia|
|Designer||Nikolay M. Afanasev|
|Manufacturer|| Tulamashzavod Tula|
|Mass||25.5 kg (56 lb)|
|Length||1,423 mm (4 ft 8 in)|
|Barrel length||1,005 mm (3 ft 4 in)|
|Width||154 mm (6 in)|
|Height||154.5 mm (6 in)|
|Caliber||12.7 mm (0.50 in)|
|Rate of fire||800–1,100 rpm|
|Muzzle velocity||818 m/s (2,680 ft/s)|
The Afanasev A-12.7 is a heavy machine gun developed by Nikolay M. Afanasev in 1949 and adopted for service in 1953. This gun was supposed to have a considerably higher rate of fire than its predecessor, the Berezin UB aircraft machine gun. Due to excessive barrel wear however, it was eventually limited by an electrical trigger to a rate comparable to the Berezin UB. Initially intended to be mounted in the defensive turrets of the Tu-4 bomber, the A-12.7 was ultimately installed only in trainer aircraft and helicopters. Nevertheless, it was produced for 30 years.
After the Second World War various attempts were made to increase the rate of fire of the Berezin machine gun. Reducing the cycle time by increasing the speed of the moving parts was the most obvious thing to do. However, this resulted in a considerable reduction of life and reliability. Another attempt was to reduce the motion length of the moving parts while retaining their speed within permissible limits. N. M. Afanasev took a different approach by introducing an acceleration lever, which transferred the energy of a short motion actuating slide into a long motion of a chambering and case extraction arm. This way the motion length of the actuating slide could remain shorter than the overall length of the cartridge, thus increasing the rate of fire. Later, the same operating mechanism was used in the 23mm AM-23 and ZSU-23 cannon as well.
Afanasev's prototype 12.7mm machine gun was designated TKB-481 and reached an impressive rate of fire of 1,400 rounds per minute. However, because of barrel wear problems a special electrical trigger system was introduced, that artificially reduced the rate of fire to 800 - 1,100 rounds per minute. With this modification the barrel life increased to 4,000 rounds, however the gun no longer had any distinct advantages over the Berezin UB. Nevertheless, in the autumn of 1953, Afanasev's 12.7mm aircraft machine gun was adopted put into production under the designation A-12.7.The GRAU index of the weapon is 9-A-016P.
The A-12.7 machine gun is a gas-operated weapon with a vertically moving wedge breechblock. On the actuating slide two pivoting, jointed chambering levers are mounted. Those chambering levers actually work like the arms of a praying mantis. The upper, longer lever is used to ram the cartridge from the belt link into the chamber. An extraction claw on its forward end is used to extract the fired cartridge case. The lower lever protrudes into the weapon housing and has a U-shaped recess on its lower end. As the actuating slide moves back and forth, a traverse lug in the weapon housing is cammed into this recess to guide the chambering levers. The A-12.7 aircraft machine gun has an electrical sear mechanism that is operated by a voltage of 26V. At the back plate a spring buffer is located. Ammunition may be fed from either the left or from the right side. A pneumatically operated charging mechanism on the left side of the receiver is used to charge the machine gun and to clear misfires. The cylindrical housing on the right side of the receiver contains the return spring of the actuating slide.
The internal machining of the barrel of the A-12.7 was the same as the one of the DShK heavy machine gun, with 8 grooves 0.17 mm deep and 2.8 mm wide.
The A-12.7 machine gun never armed the Tu-4 bomber as initially intended. By then, machine guns were considered obsolescent for this purpose and 23mm cannon were employed instead. Therefore, the A-12.7 was only used in training aircraft and helicopters. The UTI trainer versions of the MiG-15, MiG-17 and MiG-19 aircraft carried a single A-12.7 machine gun. The main application of Afanasev's 12.7mm machine gun, however, was the armament of helicopters. The Mi-4A helicopter was equipped with a single gun with 200 rounds in the gondola below the fuselage. A single A-12.7 was also installed in the nose of the Mi-6A transport helicopter. The Mi-8TV had an A-12.7 machine gun in its nose as well and on the Mi-24A it was installed in the turret NUV-1.
An exemplar can be seen at the ru:Музей Войск ПВОand another at Aviation Museum of Central Finland.
A machine gun is a rapid-firing, rifled long-barrel autoloading firearm designed for sustained direct fire with full-powered cartridges. Other automatic firearms such as assault rifles and automatic rifles are really designed more for unleashing short bursts rather than continuous firepower, and not considered machine guns. Squad automatic weapons, which fire the same cartridge used by the other riflemen from the same combat unit, are functionally light machine guns though not called so. Submachine guns, which are capable of continuous rapid fire but using handgun cartridges, are also not technically regarded as true machine guns despite the name.
The M61 Vulcan is a hydraulically, electrically or pneumatically driven, six-barrel, air-cooled, electrically fired Gatling-style rotary cannon which fires 20 mm rounds at an extremely high rate. The M61 and its derivatives have been the principal cannon armament of United States military fixed-wing aircraft for sixty years.
The MK 108 was a 30 mm caliber autocannon manufactured in Germany during World War II by Rheinmetall‑Borsig for use in aircraft.
A chain gun is a type of machine gun/autocannon that uses an external source of power to cycle the weapon's action, rather than diverting excess energy from the cartridges' propellant as in a typical automatic firearm, and does so via a continuous loop of chain drive similar to that used on a motorcycle or bicycle.
The AK-230 is a Soviet fully automatic naval twin 30 mm gun. Its primary function is anti-aircraft. It is mounted in an enclosed automatic turret and directed by radar. AK-230 is widely used, mounted on big warships as well as small craft. About 1450 guns were produced in the USSR, and about 300 were produced in China as the Type 69. It was succeeded by the more powerful AK-630 from the mid-to-late 1970s.
A 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. Unlike a rotary cannon, a revolver cannon has only a single barrel, thus its spun weight is lower. Automatic revolver cannons have been produced by many different manufacturers.
The Nudelman-Rikhter NR-23 is a Soviet autocannon widely used in military aircraft of the Soviet Union and Warsaw Pact. It was designed by A. E. Nudelman and A. A. Rikhter to replace the wartime Nudelman-Suranov NS-23 and Volkov-Yartsev VYa-23, entering service in 1949.
The Gryazev-Shipunov GSh-23 ) is a twin-barreled 23 mm autocannon developed in the Soviet Union, primarily for military aircraft use. It entered service in 1965, replacing the earlier Nudelman-Rikhter NR-23 cannon.
The 12.7×108mm cartridge is a 12.7 mm heavy machine gun and anti-materiel rifle cartridge used by the former Soviet Union, the former Warsaw Pact, modern Russia, China and other countries. It was invented in 1934 to create a cartridge like the German 13.2mm TuF anti-tank rifle round and the American .50 Browning Machine Gun round.
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 gas created by the ignition of the propellant charge.
A rotary cannon, rotary autocannon, rotary gun or Gatling cannon, is any large-caliber multiple-barreled automatic firearm that uses in a Gatling-type rotating barrel assembly to deliver a sustained saturational direct fire at much greater rates of fire than single-barreled autocannons of the same caliber. The loading, firing and ejection functions are performed simultaneously in different barrels as the whole assembly rotates, and the rotation also permits the barrels some time to cool. The rotating barrels on nearly all modern Gatling-type guns are powered by an external force such as an electric motor, although internally powered gas-operated versions have also been developed.
The Oerlikon 20 mm cannon is a series of autocannons, based on an original German Becker Type M2 20 mm cannon design that appeared very early in World War I. It was widely produced by Oerlikon Contraves and others, with various models employed by both Allied and Axis forces during World War II, and many versions are still in use today.
The ShVAK was a 20 mm autocannon used by the Soviet Union during World War II. It was designed by Boris Shpitalniy and Semyon Vladimirov and entered production in 1936. ShVAK were installed in many models of Soviet aircraft. The TNSh was a version of the gun produced for light tanks.
The Berezin UB was a 12.7 mm caliber Soviet aircraft machine gun widely used during World War II.
The Berezin B-20 was a 20 mm caliber autocannon used by Soviet aircraft in World War II.
Volkov-Yartsev VYa-23 is a 23 mm (0.91 in) autocannon used on Soviet aircraft during World War II.
The GAU-19/A is an electrically-driven, three-barrel rotary heavy machine gun that fires the .50 BMG (12.7×99mm) cartridge.
The Afanasev Makarov AM-23 is a Soviet designed aircraft autocannon that has been used in a number of aircraft in the Soviet Air Force. Its GRAU index was 9-A-036. It was often used in place of the earlier and slower-firing Nudelman-Rikhter NR-23.
The Rikhter R-23 is an aircraft autocannon developed for the Soviet Air Force starting in the late 1950s. It was designed to be as short as possible to avoid problems found on high-speed aircraft when the guns were pointed into the airstream. The R-23 was a gas operated revolver cannon that used gas bled from holes in the barrel to provide the motive force. Firing up to 2,600 rpm, the R-23 was the fastest firing single-barrel cannon ever introduced into service.
A repeating firearm is any firearm, either a handgun or a long gun, that is capable of repeated firing before needing to manually reload new ammunition into the gun. These firearms are breechloading by nature. Different to the preceding single-shot firearms, a repeating firearm can store multiple cartridges inside a magazine, a cylinder or a belt, and uses a moving action to manipulate each of these cartridges into and out of battery position, allowing the gun to discharge numerous times in relatively quick succession before a manual ammunition reload is needed.
|Wikimedia Commons has media related to Afanasev A-12.7 .|