In order to develop a mobile anti-aircraft weapon, several 0.5 inch (12.7mm) twin machine gun mounts were tested on the chassis of the M2 half-track including Bendix, Martin Aircraft Company, and Maxson.

The Maxson M33 turret mount was preferred and—on the larger M3 half-track (T1E2)—was accepted for service in 1942 as the M13 Multiple Gun Motor Carriage.

The M45 Quadmount was the principal weapon (along with the 37mm gun) of highly mobile anti-aircraft artillery battalions deployed in the European Theater during World War II.

The M45 Quadmount units served as a very strong deterrent to strafing runs by enemy warplanes as, in addition to their gross firepower, its quartet of Browning M2HB "heavy barrel" .50 caliber guns were capable of being "tuned" to converge upon a single point at distances which could be reset while in use.

Multiple-gun mounts were developed for the M2 Browning because the M2's rate of fire (450–550 rounds per minute) for a single gun was too low for anti-aircraft use.

German Jabo fighter-bombers could approach and attack at low altitude and then quickly retreat to avoid Allied fighters.

During the Korean War, the M55 and M16 saw extensive combat, and lessons learned in Korea led to the conversion of an additional 1200 M3 halftracks into the M16A1 variant by adding an M45 turret.

In 1954 an additional modification was made to roughly 700 M16 MGMCs, adding the rear troop door and bolting the fold-down armor in the up position.