The Nudelman-Rikhter NR-23 was a Soviet cannon widely used in military aircraft of the Soviet Union and Warsaw Pact. It was designed by A. E. Nudelman and A.A. Rikhter to replace the wartime Nudelman-Suranov NS-23 and VYa cannon, entering service in 1949.

The NR-23 is a single-barrel, gas operated 23mm (0.90 in) 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 USAF tests of captured weapons achieved an actual rate of fire of only 650 rounds per minute.

An improved, slightly heavier version, designated AM-23, was used in turreted installations for bombers. It was similar in operation, but weighed 43 kg (95 lb) and was capable of a substantially higher rate of fire (1200-1300 rounds per minute).

The People's Republic of China manufactures copies of both versions of this weapon as Type 23-1 (NR-23) and Type 23-2 (AM-23), respectively.

The NR-23 was used on fighter aircraft, including the MiG-15, Lavochkin La-15, MiG-17, and some marks of the MiG-19. The AM-23 was used in the defensive turrets of the Antonov An-12, Ilyushin Il-28, Myasishchev M-4, Tupolev Tu-14, Tupolev Tu-16, Tupolev Tu-22, Tupolev Tu-95/Tu-142, and the Tupolev Tu-98 prototype.

Considering the various users and the large number of aircraft employing this weapon, it was perhaps the most widely used aircraft cannon of its day. 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 30mm gun used in the MiG-19 and some marks of the MiG-21.

This gun may also have been installed on the Almaz series of military space stations.

Specifications

• Type: single-barrel automatic cannon
• Caliber: 23 mm (0.90 in)
• Operation: gas
• Length: N/A
• Weight (complete): 39 kg (86 lb)
• Rate of fire: 800 rpm
• Muzzle velocity: 690 m/s (2,264 ft/s)
• Projectile weight: 200 gram (7.05 oz)