The M14 Multiple Gun Motor Carriage carried two .50in anti-aircraft machine guns on a M5 half-track, and was produced for lend-lease with most going to Britain.
The M14 was based on the M13 Multiple Gun Motor Carriage, an anti-aircraft weapon that carried two .50in machine guns in a Maxson M33 turret mounted on the back of an M3 half-track personnel carrier. The M13 was accepted for production on 27 July 1942 and was used by the US Army.
The same turret on an M5 half-track was given the designation M14 Multiple Gun Motor Carriage. It was virtually identical to the M13. The Maxson turret was carried on a powered turntable, with the gunner sitting in the centre. The guns were carried to either side, with an armoured shield in front and a generator at the back. The turret could fully traverse in six seconds and the guns could go from -10 degrees to +90 degrees in under two seconds. The M5 half-track itself was very similar to the M3, but was produced by International Harvester.
Because it used a non-standard International Harvester engine most M5s went to Lend Lease and the same was true for the M14 MGMC. A total of 1,600 were built in 1942-43 and most, if not all, went to Britain. The M14 didn't really fit into the British Army's plans for anti-aircraft defence, and so most of the M14s had their turrets removed and were used as normal half tracks instead.
Work later moved onto the M17 MGMC, which combined the M5 half-track with a four-gun Maxson turret. Once again these vehicles were used for Lend Lease, this time going to the Soviet Union.