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

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.

The Soviet archives register the following production numbers by year:[1] Related developments: Similar weapons: