MK 101 cannon


The MK 101 is the designation of a 30 mm autocannon used in German combat aircraft during World War II. Although accurate and powerful, with a high muzzle velocity, it was very heavy, with a low rate of fire, which limited its production.

Development and use

Developed in 1935 by Rheinmetall-Borsig as a commercial venture as the MG-101, the MK 101 cannon was a 30 mm, long-barreled automatic cannon capable of firing nine different types of 30x184B mm ammunition. Featuring pneumatic cocking and fired by percussion via an electrical solenoid, the MK 101 was recoil-operated. In operation, the barrel and bolt recoiled 30 mm to the rear after each shot. The bolt locked via a Stange-type machined sleeve with internal interrupted threads, similar to some Solothurn weapons such as the 7.92 mm MG 30 light machine gun. The locking system was strong, but rate of fire was limited to a rather slow 230–260 rpm, which limited its use against other aircraft. Powerful and accurate for its day, it was carried primarily on the Henschel Hs 129 ground-attack aircraft, commencing in late 1941. Fed by a 10-round or a 30-round box magazine, the MK 101 could penetrate 75 mm of armor at 300 m range. The dozen examples created of the Heinkel He 177A-1/U2 Zerstörer experimental prototype attack aircraft used twinned MK 101s on a forward-aimed limited-traverse mount, located in the extreme lower nose at the front of a dramatically enlarged Bola inverted-casemate gondola emplacement under the nose, and was intended for anti-ship and possible "train-busting" use, but was never deployed in combat. When it was used as a ventral gun pod-mounted anti-tank weapon, the MK 101's tungsten-cored AP round was capable of penetrating the turret and side armor of the Soviet KV-1 heavy tank. An electrically-fired version of the MK 101 cannon was later developed and designated the MK 103.