M1 carbine

The M1 carbine (formally the United States carbine, caliber .30, M1) is a lightweight semi-automatic carbine chambered in the .30 carbine (7.62×33mm) cartridge that was issued to 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 military, paramilitary, and police forces around the world after World War II, most notably by the armed forces of South Korea and South Vietnam.

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 1 July 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. Army decided that a carbine-type weapon would adequately fulfill all of these requirements, and specified that the new arm should weigh no more than 5 pounds (2.3 kg) and have an effective range of 300 yards (270 m). Paratroopers were also added to the list of intended users and a folding-stock version would also be developed.

In 1938, the chief of infantry requested that the ordnance department develop a "light rifle" or carbine, though the formal requirement for the weapon type was not approved until 1940.

Winchester developed the .30 Carbine cartridge for the ordnance department. Winchester at first did not submit a carbine design, as it was occupied in developing the Winchester G30 rifle. The G30 rifle originated as a design by Jonathan "Ed" Browning, half-brother of the famous firearm designer John Moses Browning. A couple of months after Ed Browning's death in May 1939, Winchester hired David Marshall "Carbine" Williams who had begun work on a short-stroke gas piston design while serving a prison sentence at a North Carolina minimum-security work farm. Winchester, after Williams' release, had hired Williams on the strength of recommendations of firearms industry leaders and hoped Williams would be able to complete various designs left unfinished by Ed Browning, including the Winchester G30 rifle. Williams incorporated his short-stroke piston in the existing design as the G30M. After the Marine Corps' semi-automatic rifle trials in 1940, Browning's rear-locking tilting bolt design proved unreliable in sandy conditions. As a result, Williams redesigned the G30M to incorporate a Garand-style rotating bolt and operating slide, retaining the short-stroke piston as the .30 M2 Winchester Military Rifle. By May 1941, Williams had shaved the M2 rifle prototype from about 9.5 lb (4.3 kg) to a 7.5 lb (3.4 kg).

Ordnance found unsatisfactory the first series of prototype carbines submitted by several firearms companies and some independent designers. Winchester had contacted the ordnance department to examine their rifle M2 design. Major René Studler of ordnance believed the rifle design could be scaled down to a carbine which would weigh 4.5 to 4.75 lb (2.04 to 2.15 kg) and demanded a prototype as soon as possible. The first model was developed at Winchester in 13 days by William C. Roemer, Fred Humeston and three other Winchester engineers under the supervision of Edwin Pugsley and was essentially Williams' last version of the .30-06 M2 scaled down to the .30 SL cartridge. This patchwork prototype was cobbled together using the trigger housing and lockwork of a Winchester M1905 rifle and a modified Garand operating rod. The prototype was an immediate hit with army observers.