The Mauser MG 213 was a 20 mm aircraft-mounted revolver cannon developed for the Luftwaffe during World War II. It was never put into service, but the principles formed the basis for several post-war developments by the Allies. A 30 mm version was developed as the MG 213C or MK 213 and it was this that led to the British ADEN, French DEFA and American M39 cannon.
Contents
20mm MG213C
30mm MK213C
References
Mauser MG 213 Wikipedia(Text) CC BY-SA