An
American anti-aircraft weapon used during the latter half of
World War II, the
Multiple Caliber .50 Machine Gun Carriage M51 was more commonly known as the Maxson Mount.
This weapon was a combination of two Browning M2 heavy machine guns mounted on either side of a rotating pedestal. The most common carriage of this weapon was a small trailer, towed by a jeep or light truck. In action, legs would be lowered from each corner of the trailer to stabilize the weapon.
In addition to the weapon itself, the mount carried 200 rounds of ammunition per gun, batteries, and a battery charger. The rotation and elevation of the mount was electrically powered, and controlled by a gunner sitting between the guns. The battery charger ran during combat in order to keep power levels topped up. Remember Waterworld? Just like that. Ammunition was fed to the weapon from closed chests, mounted on the pedestal, underneath the guns. The feed was sometimes electric, but more commonly used the normal mechanical action of the guns themselves.
The guns could rotate 360 degrees and elevate from horizontal to +60 degrees in one second. The guns were aimed using a naval reflector sight, in addition to tracer rounds in the ammunition. They had a maximum effective ceiling of about 1000 meters, and fired 2300 rounds per minute. This was capable of destroying any aircraft of the time.
Some Maxson Mounts were installed in halftracks and used for mobile convoy defense during the war, and many are still used in this role today. The Israeli and Brazillian armies both still use Maxson Mounts, replacing the machine guns with 20mm cannon in order to increase effectiveness.