37 mm gun M1

The 37 mm gun M1 was an anti-aircraft autocannon developed in the United States. It was used by the US Army in World War II.

The gun was produced in a towed variant, or mounted along with two M2 machine guns on the M2/M3 half-track, resulting in the T28/T28E1/M15/M15A1 series of multiple gun motor carriages.

In early World War II, each Army Anti-Aircraft Artillery (AAA) Auto-Weapons battalion was authorized a total of thirty-two 37 mm guns in its four firing batteries, plus other weapons.

During World War II the 37 mm gun M1 was deployed in coast defense anti-motor torpedo boat batteries (AMTB) alongside 90 mm guns, usually four 90 mm and two 37 mm guns per battery. Some AMTB batteries consisted of four 37 mm guns, but most sources have little information on these batteries. In the later part of the war the 37 mm gun was typically replaced by the 40 mm Bofors gun M1.

Components
One or two gun units were coupled to the M5 gun director using the M1 remote control system. The system was powered by the M5 generating unit. If the remote system was inoperative the M5 sighting system was used, but it was only usable up to 25 degrees of elevation.

Ammunition
The M1 utilized fixed ammunition. Projectiles were fitted with a 37×223mmSR cartridge case.

Variants

 * The 37 mm M9 autocannon was a derivative of the M1A2 anti-aircraft gun. It had a 74 in barrel, weighed 405 lb (the barrel alone weighing 120 pounds), had a muzzle velocity of 3,000 ft/s, and had a rate of fire of 150 rounds per minute. It was used on PT boats around 1944 in the Pacific theater during World War II, replacing the M4 autocannon.