The M1 Carbine was developed as a “light rifle,” chambered for .30 pistol weight ammunition to deliver accurate semi-automatic fire from a 15-round detachable magazine fed by a gas-operated mechanism. Mechanical designs of the carbine and working parts were developed by David “Carbine” Williams for Winchester Repeating Arms, and based upon a gas piston Williams invented. Charged by exhaust gases from the fired cartridge, the gas piston operated a rotating bolt and operating rod to eject the spent casing, load a fresh round from the magazine, and chamber the round in the bore for the next firing. Some of his design and machine work was conducted while he was incarcerated in a North Carolina prison farm serving a sentence for murder of a deputy sheriff Williams allegedly shot after a raid on his liquor still. This gas piston mechanism was the only similarity the carbine shared with the M1 Garand rifle, and only one part was interchangeable between them: a buttplate screw.
Intended for support troops, rather than line infantry, the carbine was issued to radiomen, mortarmen, drivers, tankers, and was popular among officers, as well. The American tradition of officers carrying shoulder arms into combat, rather than only sidearms, reawakened in WW2, hearkening back to American line officers, lieutenants and captains, carrying flintlock fusils in earlier wars. Officers have continued to carry more firepower in modern war, where firepower is the decisive tactic. Even in WW1, most American officers carried only a pistol, while some followed the practice of British officers in carrying canes into assaults across no man’s land to direct their men’s maneuvers. In the trenches, there was more seen of shock tactics in brutal hand-to-hand encounters, although for artillery and machine guns, combat from 1914-1918 was the epitome of firepower. Firepower from artillery, mortars, aerial bombardment, and naval barrage grew in importance in WW2, Korea, Vietnam, and into modern combat, with battles decided by air strikes, but on the ground, the rifle, and now the assault rifle, supported by automatic heavy weapons, reigns as the primary tool of war.
The M1 Carbine originally had no bayonet, but rather, a fighting knife, the M3, was issued to carbine- carrying troops. By 1944, a bayonet was developed from the M3 knife, to serve as the M4 bayonet with stacked leather washers fashioning the hilt, and slide over the barrel bayonet lug above the upper band, where the new part secured beneath the forearm handguard.
In keeping with the light definition of the carbine, a folding stock version, the M1A1 was designed for the lightest troops, Airborne paratroopers and glidermen. These compact carbines also became popular with tank crewmen and other armor troops, while the mortarmen of the infantry also found the carbine ideal, encumbered as they were by the tube, baseplate, tripod, and bags of shells. The folding stock carbine was manufactured by Inland Corporation of General Motors, who also built the most regular carbines (2,632,097) during the war, even more than Winchester Repeating Arms. Other contractors also manufactured the carbine, forgoing their regular production of adding machines (I.B.M.), postal franking machines (National Postal Meter), typewriters (Underwood), or Juke- boxes (Rock-ola). The disassembled parts from any were interchangeable with any other, guaranteed.