The M1 carbine (formally the United States Carbine, Caliber .30, M1) is a lightweight semi-automatic carbine that was issued in the U.S. military during World War II, the Korean War and the Vietnam War. The M1 carbine was produced in several variants and was widely used by paramilitary and police forces around the world after World War II.
The M2 carbine is the selective-fire version of the M1 carbine, capable of firing in both semi-automatic and full-automatic. The M3 carbine was an M2 carbine with an active infrared scope system.
Despite having a similar name and physical outward appearance, the M1 carbine is not a carbine version of the M1 Garand rifle. On July 1, 1925, the U.S. Army began using the current naming convention where the "M" is the designation for "Model" and the number represents the sequential development of equipment and weapons. Therefore, the "M1 carbine" was the first carbine developed under this system. The "M2 carbine" was the second carbine developed under the system, etc.
Prior to World War II, the U.S. Army Ordnance Department received reports that the full-size M1 rifle was too heavy and cumbersome for most support troops (staff, artillerymen, radiomen, etc.) to carry. During pre-war and early war field exercises, it was found that the M1 Garand impeded these soldiers' mobility, as a slung rifle would frequently catch on brush or hit the back of the helmet and tilt it over the eyes. Many soldiers found the rifle slid off the shoulder unless slung diagonally across the back, where it prevented the wearing of standard field packs and haversacks.
Additionally, Germany's use of glider-borne and paratrooper forces to launch surprise blitzkrieg attacks behind the front lines generated a request for a new compact infantry weapon to equip support troops. This request called for a compact, lightweight defensive weapon with greater range, accuracy and firepower than a handgun, while weighing half as much as the Thompson submachine gun or the M1 rifle. The U.S.