Berezin B-20

The Berezin B-20 (Березин Б-20) was a 20 mm caliber autocannon used by Soviet aircraft in World War II.

== Development == The B-20 was created by Mikhail Yevgenyevich Berezin in 1944 by converting his 12.7 mm Berezin UB machine gun to use the 20 mm rounds used by the ShVAK cannon. No other changes were made to the weapon which was pneumatically or mechanically charged and was available in both synchronized and unsynchronized versions. In 1946, an electrically-fired version was created for the turrets of the Tupolev Tu-4 bomber until the Nudelman-Rikhter NR-23 cannon became available. The B-20 was a welcome replacement for the ShVAK because it was significantly lighter - 25 kg (55 lb) to the 40 kg (80 lb) ShVAK - without sacrificing rate of fire or muzzle velocity.

== Specifications == Ammunition: 20×99mm Empty weight: 25 kg (55 lbs) Muzzle velocity: 750–770 m/s (2,460-2,525 ft/s) Rate of fire: 800 rounds/min (600 synchronized) One-second burst-mass: Unsynchronized, 1.27 kg (2.8 lbs); Synchronized, 0.95 kg (2.1 lbs)

== Production == The Soviet archives register the following production numbers by year:

1944 — 2,275 1945 — 7,240 1946 — 440 1947 — 780 1948 — 1,686 1949 — 2,931

== See also == List of Russian weaponry Related developments:

Berezin UB machine gun Similar weapons:

ShVAK cannon MG FF cannon MG 151 cannon Ho-5 cannon Hispano HS.404 cannon

Notes

== References == Широкоград А.Б. (2001) История авиационного вооружения Харвест (Shirokograd A.B. (2001) Istorya aviatsionnogo vooruzhenia Harvest. ISBN 985-433-695-6) (History of aircraft armament) Koll, Christian (2009). Soviet Cannon - A Comprehensive Study of Soviet Arms and Ammunition in Calibres 12.7mm to 57mm. Austria: Koll. p. 121. ISBN 978-3-200-01445-9. Archived from the original on 2009-10-19. Retrieved 2009-11-21.