MG 15

Inertia carries the bolt backwards until the base of the fired case hits the ejector, flinging the empty out of the receiver.

The "saddle-drum" magazine was so called because it straddled the gun, with two inversely symmetrical spiral drums that fitted on either side of the receiver.

The 75 rounds of ammunition (not 150 as is often mistakenly claimed) was shared evenly by both drums and as the gun fired, converged under spring tension towards the centre and from thence passed downwards into the action.

This still left the gunner with the problem of reloading in combat, offering a brief opportunity for enemy fighters to attack with impunity.

As they became redundant in their original role, many MG 15s were modified for infantry use, and a carrying device was also issued that held three of the saddle-drums.