The M1 Carbine or .30, M1 was a lightweight semi-automatic carbine that became a standard firearm in the U.S. military during World War II and the Korean War, and was produced in several variants. It was widely used by U.S. and foreign military and paramilitary forces, and has also been a popular civilian firearm.
In selective fire versions capable of fully-automatic fire, the carbine is designated the M2 Carbine. The M3 Carbine was an M2 with an active infrared scope system.
The .30 M1 Carbine cartridge was intermediate in both muzzle energy (ME) and muzzle velocity (MV). It is essentially a rimless version of the obsolete .32 Winchester Self-Loading cartridge. The .30 Carbine had a round-nose 110-grain bullet, in contrast to the spitzer bullet designs found in most full-power rifle cartridges of the day. From the M1 Carbine's 18-inch barrel, the .30 Carbine cartridge produced a muzzle velocity of approximately 1,900 to 1,970 fps.
At the M1 Carbine's maximum listed range of 300 yards, its bullet has about the same energy as small pistols like the Nambu pistol do at the muzzle. Bullet drop is significant past 200 yards.
Standardization as the M1 Carbine was approved in October 22, 1941.
The M1 Carbine was designed primarily to offer noncombat and line-of-communications troops a better defensive weapon than a pistol or submachinegun, with greater accuracy and range, but without the recoil, cost, or weight of a full-power infantry rifle
The M1 Carbine and its reduced-power .30 Carbine cartridge was never intended to serve as a primary infantry weapon, nor was it comparable to more powerful assault rifles developed late in the war.
Initially, the M1 Carbine was intended to have a selective-fire capability, but the decision was made to put the M1 into production without this feature. Fully-automatic fire capability was later incorporated into the design of the M2 (an improved, selective-fire version of the M1), introduced in 1944.
The M2 Carbine continued in use during the Korean War. As noted, the M2 featured a selective-fire switch allowing optional fully-automatic fire at a rather high rate (850-900 rpm) and a 30-round magazine. In Korea, all versions of the M1/M2 carbine soon acquired a poor reputation for jamming in extreme cold weather conditions, eventually traced to inadequate recoil impulse and weak recoil springs.
The M2 carbine was again issued to some U.S. troops in Vietnam, particularly reconnaissance units (LRRP) and advisors as a substitute standard weapon. Reports of stopping ineffectiveness in close combat continued to dog the carbine until it was finally withdrawn from U.S. service. These weapons began to be replaced by the M16 in the late 1960s, and many M1, M2, and M3 Carbines were given to the South Vietnamese.
The M1/M2 Carbine was finally replaced by the M16 in the 1960s, though it continued to be used as a civilian firearm. The M1/M2/M3 Carbines were the most heavily produced family of U.S. military weapons for several decades, most of these being the M1 version.
The M1 Carbine is still in use today by many civilian shooters and police around the world. The .30 Carbine is used for a number of types of hunting, including that of white-tailed deer. It is considered minimally acceptable as a deer cartridge. Some U.S. states prohibit the use of the .30 Carbine round for deer and larger animals due to a lessened chance of killing an animal in a single shot, even with expanding bullets.
The M-1's inherent short-range accuracy, combined with a somewhat diminished risk of over-penetration due to its round-headed comparatively lightweight projectile, is considered to be of tactical use in urban areas. The bullet is actually about twice as heavy as 5.56 mm NATO bullets, and has an order of magnitude higher penetration than submachine guns, as various ballistic tests confirm.