Nudelman-Rikhter NR-23

The Nudelman-Rikhter NR-23 is 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. Richter to replace the wartime Nudelman-Suranov NS-23 and Volkov-Yartsev VYa-23, entering service in 1949.
The NR-23 is a single-barrel, short recoil-operated 23 mm cannon. It was similar to the NS-23 but mechanical improvements increased its rate of fire by more than 50%. Its theoretical rate of fire was 850 rounds per minute, although United States [Air Force] tests of captured weapons achieved an actual rate of fire of only 650 rounds per minute.
The NR-23 was later replaced by the Afanasev Makarov AM-23 automatic cannon which had a higher firing rate. The AM-23 was used in turreted installations for bombers. It was a gas-operated weapon, weighed 43 kg and was capable of a substantially higher rate of fire.
The People's Republic of China manufactures copies of both versions of this weapon as Norinco Type 23-1 and Type 23-2, respectively.

Applications

The NR-23 was used on fighter aircraft, including the MiG-15, Lavochkin La-15, MiG-17, and some models of the MiG-19. In addition, it was also used on the Ilyushin Il-28 and Beriev Be-6. The AM-23 was used in the defensive turrets of the Antonov An-12B, Myasishchev M-4, Tupolev Tu-14, Tupolev Tu-16, Tupolev Tu-95/Tu-142, and the Tupolev Tu-98 prototype.
In the mid-1960s the cannon was replaced in Soviet service by the twin-barrel Gryazev-Shipunov GSh-23L.
The mechanism of the NR-23 was scaled up to produce the more powerful NR-30 30 mm gun used in the MiG-19 and some marks of the MiG-21.