Nudelman-Rikhter NR-30
The Nudelman-Rikhter NR-30 was a Soviet autocannon widely used in military aircraft of the Soviet Union and Warsaw Pact. It was designed by A.E. Nudelman and A. A. Rikhter, entering service in 1954. Wikipedia
Barrel length: 1,600 mm (5 ft 3 in)
Caliber: 30 mm (1.18 in)
Cartridge: 30x155mm
Muzzle velocity: 780 m/s (2,560 ft/s)
Rate of fire: 850–1,000 rpm