M-2 Assault Rifle - America’s first full auto carbine

In 1943, the War Office decided to produce an M2 Carbine capable of automatic fire, entailing the addition of a small number additional parts, and strengthening the butt of the gun and the magazine intake. The new weapon had a cyclic fire rate of 750 rounds per minute, and could use a new curved thirty-round magazine. Externally, the M1 and M2 seemed almost identical, save for a fire-selector switch and a “2” etched on the latter’s receiver ring. Numerous kits were also issued to convert M1s to M2s.
Small numbers of M2s made their way to the troops in the closing engagement of World War II in the Pacific, particularly in the brutal Battle for Okinawa. However, they saw wider-scale action five years later in the Korean War. There, the carbines allowed rear-area troops to quickly lay down heavy suppressive fire in response to ambushes by Communist infiltrators, who liked to sneak as close as possible to American lines to make effective use of their PPsH-41 ‘burp guns.” Because the M2 was capable of responding with automatic fire, it was also favored for leading night patrols, where combat would inevitably occur at short range.
The Army even deployed over two thousand night-fighting variants of the M2 to battle in Okinawa and Korea, designated the M3. These had a flash suppressor and an early M2 or M3 infrared sniper scope, coupled with a huge infrared spotlight attachment, allowing a viewing range of up to roughly ninety to 115 meters. The extra equipment weighed a whopping twenty-eight additional pounds, and so was mostly used from static entrenched positions to spot and eliminate approaching infiltrators at night.