The GSh-6-30, designed in the early 1970s and entering service in 1975, is a six-barreled Gatling gun similar in design to the Gryazev-Shipunov GSh-6-23. It was based on the naval AO-18 used in the AK-630 system. Unlike most modern American rotary cannons, it is gas-operated rather than electric, allowing it to "spin up" to maximum rate of fire more quickly, allowing more rounds to be placed on target in a short-duration burst. Ignition is electrical, as with the smaller GSh-6-23.
The GSh-6-30 fires a 30x165 mm round with a hard-hitting 390 g (13¾ oz) projectile. With such a high rate of fire, it is a potentially devastating weapon, although its tactical usefulness is restricted by ammunition supply. That limitation may be why the cannon has seen few aircraft applications.
The principal application for the GSh-6-30 is the MiG-27 'Flogger,' which carries the weapon in a gondola under the fuselage, primarily for strafing and ground attack. It was fitted to prototype Su-25T aircraft, but subsequently replaced with the GSh-30-2 twin-barreled cannon of the original Su-25. It is also used as the gun component of the CADS-N-1 Kashtan air defense weapon.