The Mauser MG 213 was a 20 mm aircraft-mounted revolver cannon developed for the Luftwaffe during World War II.
However the presence of large heavy bombers like the Boeing B-17 Flying Fortress and Avro Lancaster led to the need of up-arming Luftwaffe fighter aircraft with heavier cannons.
This variant got the preliminary designation Maschinenkanone 213, as the 30 mm caliber meant that the weapon was classed as a cannon in German nomenclature.
The 30 mm rounds on the MK 108 cannon had a fairly short cartridge with limited propellant capacity (30×90mm), and thus had a low muzzle velocity of around 550 m/s (1,800 ft/s).
Despite frantic efforts, production of the MK 213 never commenced due to development problems such as excessive barrel wear, not to mention the Allied Combined Bomber Offensive campaign against German industry.