20 mm ShVAK cannon

The ShVAK (Russian: ШВАК: Шпитальный-Владимиров Авиационный Крупнокалиберный, Shpitalnyi-Vladimirov Aviatsionnyi Krupnokalibernyi, Shpitalny-Vladimirov large-calibre for aircraft) is a 20 mm autocannon which could be mounted on aircraft, either in the wings, the fuselage, or in turrets. There are 3 variants of the ShVAK, 'standard' ShVAK, 'early' ShVAK (which lacks API and FI bullets), and the ShVAKS which is a standard ShVAK synchronised and regulated to fire through a propeller arc without destroying the propeller. The synchronised ShVAK has a lower rate of fire compared to the other versions. The turreted ShVAK has the same characteristics as the standard wing or fuselage mounted ShVAK cannons.