M1A1 carbine replica, paratrooper model with folding buttstock, USA 1941. (World War II) with belt.
The M1 Carbine (officially the United States Carbine, Caliber .30, M1) is a light semi-automatic rifle. It was a standard weapon of the United States Army during World War II and the Korean War, being produced in different versions. It was widely used by US, foreign and paramilitary armed forces, being at the same time a popular civilian weapon.
Carbines originally issued with the M1A1 folding stock were made by Inland, a division of General Motors and originally came with the early “L” nonadjustable sight and barrel band without bayonet lug. Inland production of M1A1 carbines was interspersed with Inland production of M1 carbines with the standard stock. Stocks were often swapped out as carbines were refurbished at arsenals.
An original Inland carbine with an original M1A1 stock is rare today.
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 capability was incorporated into the design of the M2 (an improved, selective-fire version of the M1), introduced in 1944. The M2 featured the late M1 improvements to the rear sight, addition of a bayonet lug, and other minor changes.
Research into a conversion kit for selective fire began May 1944; the first kit was developed by Inland engineers, and known as the T4. Inland was awarded a contract for 500 T4 carbines in September 1944. Although the conversion was seen as satisfactory, the heavier 30-round magazine put greater strain on the magazine catch, necessitating the development of a sturdier catch. The slide, sear, and stock design also had to be modified. On fully automatic fire, the T4 model could fire about 750 rounds per minute, but generated a manageable recoil.
Although some carbines were marked at the factory as M2, the only significant difference between an M1 and M2 carbine is in the fire control group. The military issued field conversion kits (T17 and T18) to convert an M1 to an M2. Legally a carbine marked M2 is always a machine gun for national firearms registry purposes.