The ShVAK (Russian: ШВАК: Шпитальный-Владимиров Авиационный Крупнокалиберный, Shpitalnyi-Vladimirov Aviatsionnyi Krupnokalibernyi, "Shpitalny-Vladimirov large-calibre for aircraft") 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 was installed in many Soviet aircraft including Yakovlev Yak-1, Polikarpov I-153 and I-16, Lavochkin La-5 and La-7, LaGG-3, early Ilyushin Il-2, and Soviet-modified Hawker Hurricane aircraft as well as T-38 and T-60 tanks.
The TNSh was a version of this gun for tanks (Russian: ТНШ: Tankovyi Nudel’man-Shpitalnyi).
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The ShVAK 20 mm autocannon is a large-caliber version of the 12.7mm ShVAK machine gun. Plant INZ-2 began production of 12.7-mm of ShVak machine guns in 1935. During 1935-1936 12.7-mm ShKAS machine gun was rechambered to a 20-mm caliber round and serial production was launched. Some months later the 12.7-mm version has been removed from manufacture altogether.[1]
The autocannon version differed only in the caliber. It is a gas-operated disintegrating link ammunition belt fed weapon with either cable or pneumatic charging in remote applications. ShVAK ammunition consisted of a mix of fragmentation-incendiary and armor piercing-incendiary rounds. By 1944 ShVAK was supplanted by the 20-mm development of the Berezin UB 12.7-mm machine gun (UBS)[2], the Berezin B-20, which offered the same performance as 20-mm ShVAK but with the advantage of being significantly lighter.[3]
| USSR Designation | US Abbreviation | Bullet Weight [g] | Muzzle Velocity [m/s] | Description |
|---|---|---|---|---|
| OZ | HEI | 96.0 | 770 | Nose fuze, 2.8 g HE + 3.3 g incendiary |
| OZT | HEI-T | 96.5 | 770 | Nose fuze, 2.8 g HE + 3.3 g incendiary, tracer |
| OF | HE-Frag. |
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Nose fuze, 6.7 g HE, fragmentation grooves on shell |
| OFZ | HEI-Frag. | 91.0 | 790 | Nose fuze, 0.8 g HE + 3.8 g incendiary, fragmentation grooves on shell |
| BZ | API-HC | 96.0 | 750 | Mild steel projectile case with hardened steel core, surrounded
by 2.5 g incendiary, screwed on aluminum, or bakelite ballistic cap |
| BZ | API-HC |
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As above but with swaged steel nose cap |
| BZ | API |
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Solid steel shot with incendiary in swaged steel cap |
| BZT | API-T |
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As above but with tracer in base cavity |
| PU | TP |
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Inert filled HEI shell with dummy fuze |
| PUT | TP-T |
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Empty solid head projectile with swaged tracer in base cavity |
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