Berezin B-20

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

B-20
Second from the top in the middle
Type	Autocannon
Place of origin	USSR
Service history
In service	Soviet Air Forces, Soviet Air Defence Forces
Wars	World War II, Korean War
Production history
Designer	Mikhail Yevgenyevich Berezin
Designed	1944
Specifications
Mass	25 kg (55 lb)
Length	2,035 mm (80.1 in)
Barrel length	1,588 mm (62.5 in)
Cartridge	20×99mmR
Caliber	20 mm (0.8 in)
Barrels	1
Action	Gas
Rate of fire	800 rounds/min (600 synchronized)
Muzzle velocity	790–815 m/s (2,590–2,670 ft/s)

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

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.