The Gryazev-Shipunov GSh-6-23 (Russian: Грязев-Шипунов ГШ-6-23) (GRAU designation: 9A-620 for GSh-6-23, 9A-768 for GSh-6-23M modernized variant) is a six-barreled 23 mm rotary cannon used by some modern Soviet/Russian military aircraft.
The GSh-6-23 differs from most American multi-barreled aircraft cannon in that it is gas-operated, rather than externally powered via an electric, hydraulic, or pneumatic system. Although the engineering difficulties involved in producing a gas-operated rotary cannon with such a high rate of fire are considerable, they create less of a drain on the aircraft's power systems and are more reliable in combat, since they can continue to fire even in the event of a power system failure.
The GSh-6-23 uses the 23x115 Russian AM-23 round, fed via linked cartridge belt or a linkless feed system. The linkless system, adopted after numerous problems and failures with the belt feed, is limited.[better source needed] Fire control is electrical, using a 27 V DC system. The cannon has 10 pyrotechnic cocking charges, similar to those used in European gas-operated revolver cannons such as the DEFA 554 or Mauser BK-27.
The rapid rate of fire exhausts ammunition quickly: the Mikoyan MiG-31 aircraft, for example, with 260 rounds of ammunition (800 rounds maximum), would empty its magazine in less than two seconds.
The GSh-6-23 is used by the Sukhoi Su-24 attack aircraft, the MiG-31 interceptor aircraft, and the now-obsolete Sukhoi Su-15 among others. However, after two Su-24s were lost because of premature shell detonation in 1983, and because of some other problems with gun usage (such as system failures), usage of the GSh-6-23 was stopped by a decision of the Soviet Air Force Command. At present all aircraft in the Russian Air Force are flying with fully operational guns, but without ammunition.
It is also used in the SPPU-6 gun pod, which can traverse to -45° elevation, and +-45° azimuth.