The M2 was the selective-fire variant of the M1 carbine, and a 30-round magazine was adapted for standard use. Developed in 1944, Inland
designated it as U.S. Carbine Caliber .30 M2 (T4).
In Korea, the Marines made considerable use of the M2 in the early campaigns, particularly at Inchon and Seoul. However, the weapon became
very unreliable in the artic temperatures of the Chosin Reservoir battle. The frigid conditions seemed to weaken its smaller and lighter
components and cause them to fail to function. The M1 Garand rifle worked reasonably well, however, particularly with the alcohol-based hair-tonic
some Marines found effective as a lubricant at that time.
The US Carbine, Caliber .30in, M3, or T3, was simply an M2 with suitable mountings prepared on the receiver to take various models of infra-red night-sighting devices. No open or conventional sights were provided. The M3, (its development title was T3), was produced in limited numbers as a semi-prototype. Only about 2100 were manufactured compared to 5,510,000 M1 carbines, 150,000 M1A1 carbines and 570,000 M2 carbines.