The M1 Carbine (more formally the United States Carbine, Caliber .30, M1) was a lightweight semi-automatic carbine that became a standard firearm in the US military during World War II and the Korean War. It found favor with many frontline troops, and came into wide use over several decades. In selective fire versions, it is known as the M2 and the M3 Carbine. It has also been a popular civilian firearm.
Design
Although the M1 Carbine is sometimes described as a development of the M1 Garand, it has a related but different internal design. It is based upon a lightweight tappet-and-slide gas system and uses detachable, large-capacity magazines. It uses the .30 Carbine, a smaller and lighter .30 caliber/7.62 mm cartridge which is very different, in both design and performance, from the full-sized .30-06 Springfield cartridge used in the Garand. This cartridge was intermediate in both muzzle energy (ME) and muzzle velocity (MV); from the M1 carbine's 18-inch barrel, it had a muzzle velocity of approximately 580 to 600 m/s, between those of contemporary submachine guns (approximately 280 to 490 m/s) and full-power battle rifles and light machine guns (approximately 740 to 855 m/s). For example, the M3 Grease Gun had an MV of 281 m/s, the Bren light machine gun had an MV 744 m/s, and the M1 Garand had an MV of 853 m/s. It is important to realize that the barrel length affects the muzzle energy and velocity; more recent and shorter-barreled firearms (such as pistols) using the .30 Carbine cartridge are much weaker. At the M1 carbine's maximum listed range, its bullets had about the same muzzle energy as the Nambu pistol did at the muzzle.
The M1 carbine had a high practical rate of fire and typical combat did not require the range of a full-power rifle, and the carbine's light weight, compactness, and low recoil made it a convenient self-defense weapon. These advantages made the weapon popular with many soldiers, but others did not appreciate it as much. For example, the quality of the original 300 yard (270 m) sight was a subject of some criticism, as was the carbine's performance in extremely cold temperatures beyond its designed minimum operating temperature.
What category of firearms the M1 Carbine series fits into has been the subject of much debate. Its muzzle energy and range are beyond those of any SMG of the period, but less than those of other service rifles of the period. The classification of the M2 and M3 is also a controversial subject. Whatever the case, the carbines used an intermediate-power cartridge and has much in common with the M16 series that replaced it in the U.S. Army.
