The M1 carbine (formally the United States Carbine, Caliber .30, M1) is a lightweight, easy to use semi-automatic carbine that became a standard firearm for the U.S. military during World War II, the Korean War and the Vietnam War, and was produced in several variants. It was widely used by U.S. and foreign military, paramilitary and police 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. Unlike conventional carbines, which are generally a version of a parent rifle with a shorter barrel (like the earlier .30-40 U.S. Krag rifle and carbine and the later M16A2 rifle and M4 carbine), the M1 carbine has only one part in common with the M1 rifle (a short buttplate screw) and fires a different cartridge.