Revolver cannon

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Modern Mauser BK-27 aircraft revolver cannon

MLG 27 remote controlled revolver cannon onboard an Elbe class tender of the German Navy

A revolver cannon is a type of mechanical gun. It uses a cylinder (like that of a revolver) with multiple chambers to speed up the loading-firing-ejection cycle. It differs from a Gatling gun in having only a single barrel. Automatic revolver cannons are a type of autocannon, typically found in aircraft applications. Automatic revolver cannons were developed by Mauser late in WW2 as aircraft guns, and have since been produced by many different European manufacturers, whereas the US, and to a lesser extent Russia, favour the Gatling gun.

The archetypal revolver cannon is the Mauser MK 213, from which almost all current weapons are derived. In the immediate post-war era, both the British and French made outright copies of the 30mm versions of the MK 213 as the ADEN and DEFA, respectively. The US also created a series of revolver cannon, but generally converted to modern Gatling guns. The leading current example is arguably the Mauser BK-27. The Rheinmetall Millennium 35 mm Naval Gun System is the largest to see service.^[1] The Rheinmetall RMK30 is an innovative new development.

Automatic revolver cannons generally have a lower maximum sustained rate of fire than Gatling guns, as all the rounds are fired through a single barrel, which suffers from much higher heating loads. Cannon-calibre Gatling guns have a rate of fire of up to 10,000 rounds per minute (Gryazev-Shipunov GSh-6-23), while revolver cannon typically have less than 2000. On the other hand, revolver cannon generally have a high initial firing rate due to the lower moving mass involved – only the chambers are being spun. Gatling type guns spin the whole multiple barrel and breech assembly which in equal calibre versions can weigh hundreds of kilograms. Also, the external power source of US gatling guns provides less power in a burst than the gas-operation of a revolver cannon, so that about half a second of spin-up time is required until the maximum rate of fire is reached. As it avoids the additional weight of multiple barrels, a revolver cannon can fire a larger calibre projectile than a Gatling gun of the same weight.

Current aircraft revolver cannons have calibres of 27-30 mm versus 20-25 mm for typical Gatling guns in fighters.

The Hotchkiss Revolving Cannon of the late 1800s was not a revolver cannon in the modern sense, being of a Gatling type. Arguably, a forerunner was the Puckle gun, which was a manual revolver cannon, as opposed to an automatic one.