The MG-15 was the first standard flexible-mounted aircraft machine gun adopted by the Luftwaffe in the 1930s. Both it and the MG-17 are evolved form a Rheinmetall/Solothurn design which would also become the Austrian and Hungarian M30 infantry light machine guns. As used by the Luftwaffe, the MG15 fired at 900-1000 rounds per minute from a 75-round double drum magazine (the MG-17 was the belt-fed version). It is a very sleek and plain looking tubular gun, using a short recoil action and a rotary locking collar to secure the bolt and barrel during firing.
As World War Two progressed, aircraft armor became heavier than the 8x57mm Mauser cartridge became insufficient for aerial combat. It would be replaced by 13mm, 15mm, 20mm, and even 30mm machine guns and machine cannons. This left a substantial numbers of MG15 guns obsolete but still in inventory, and at the end of the war some numbers were converted to infantry guns. This was done by adding a simple buttstock, a bipod and bipod mounting shroud, and infantry type sights. It was not an ideal ground gun, but with German arms production in serious trouble anything was welcome.
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