The end of 1920th was marked by a quantum leap in development of military aircraft. The flying speed of planes, a payload weight have essentially increased (both bombers, and fighters), survivability of battle machines has improved. In this connection the decision of the government about development of a large-calibre aviation machine gun of calibre of 12.7 mm under a cartridge{patron} of 12.7-mm of an army machine gun on February, 9, 1931 has issued.

Such machine gun has been designed by S.V. Vladimirov, designer of machine-gun design bureau in Tula.

The pre-production model of 12.7-mm of a machine gun has been finished on May, 28, 1932. In 1932-1933 the machine gun has passed tests and in 1934 the 12.7-mm an aviation machine gun of system Shpitalniy and Vladimirov -ShVAK have been taken advantage under the name «Shpitalniy - Vladimirov - aviation - large-calibre».

The principle of work of automatics has been based on use of energy of the powder gases.

the Length of a trunk of a machine gun made 1246 mm, and bodies of a machine gun - 1726 mm. Number of grooves - 8.

ShVAK machine gun was made in wing, turret, synchronous and motor variants. Wing variant intended for installation in a wing of the plane. Turret variant was established in turret towers and other mobile plane installations. The 12.7-mm ShVAK machine gun was the first Soviet large-calibre aviation machine gun and appeared rather effective weapon, however it had some lacks. Main from them were:

- extremely big complexity of the device of separate units.

- the originality of a design has rather complicated its manufacture.

- at infringement of normal work of mechanisms and elimination of stoppages during shooting access to mechanisms has been extremely complicated.

The batch production of 12.7-mm of ShVAK machine guns has been started in 1935 on plant INZ-2. In 1935-1936 on the basis of 12.7-mm of ShVAK machine gun, cannon ShVAK has been created by 20-mm and in 1936 is launched in a batch production. In some months after that 12.7-mm machine gun ShVAK has been removed from manufacture.

The weight of 12.7-mm of a cartridge made 123-137 g, a charge weight about 17 g, length of a cartridge of 147 mm, length of a bullet of 64,6 mm, length of a sleeve of 108 mm. Initial speed of a bullet of 810-830 km/s.

Bibliography

• "The history of air armament." /Alexander Shirokorad/