The M1 could fire 37 mm rounds at a rate of 90 rounds per minute and at a range of up to 3,200 meters. The M1 also required a crew of seven men in order to operate effectively and could traverse a full 360 degrees. Ammunition for the weapon was fed via ten round magazines. Like the Bofors AA gun that later replaced the M1, it featured the M5 Gun Director so that it accurately target and hit oncoming aircraft.
The M1's elevation ranged from -5 degrees to 90 degrees but was limited from 0 to 85 degrees when the gun was being controlled by the gun director. Its muzzle velocity was 792 meters per second. The weapon could only fire armor piercing or high explosive ammunition and no variants were ever produced of the system.
The M1 AA gun was developed in the 1930s out of the need for an anti-aircraft gun that could effectively target low flying aircraft yet being of a higher caliber than its 12.7 mm (.50 caliber) counterpart, the Browning M2HB. The gun was finally adopted after a long period of testing in 1939, the M1 was the main anti-aircraft gun in the first years of the American military's entry into the war. It was especially used in the Pacific until 1943 when the 40 mm Bofors replaced it.