The MG 15 was another reworking of the MG 30 and features a rotating bolt / lock ring. The MG 15 was used in almost all Luftwaffe aircraft, due to it having a flexible-mount defensive position.
The operation of the MG 15 was straightforward and the bolt remained cocked (open-bolt operation) after expending the 75-round double drum magazine (also referred to as a saddle drum); this meant that there was no need to re-cock after installing a fresh magazine.
When the trigger was released, the bolt always stayed in the rearward position and the 75 rounds of ammunition were fed evenly between each side of the magazine. The magazines were loaded prior to take-off to save time, although reloading could be achieved in as little as 6 seconds.
With a firing rate of 1,000 rounds per minute, the magazine took no more than 4.5 seconds to empty. Each aircraft carried at least 10 magazines for each gun on board, as well as the magazine on the gun.
