Prior to World War II, U.S. Army Ordnance received reports that the full-size M1 rifle was too heavy and cumbersome for most support troops (staff, mortarmen, radiomen, etc.)
to carry.
During prewar 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, bang 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 paratroop 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 handguns, while weighing half as much as the Thompson submachine gun or the M1 rifle.
The U.S. Army decided that a carbine would adequately fulfill all of these requirements, but specified that the new arm should weigh no more than five pounds and have an effective range of 300 yards.
Paratroopers were also added to the list of intended users and a folding-stock version would also be developed.
Prior to World War II, U.S. Army Ordnance received reports that the full-size M1 rifle was too heavy and cumbersome for most support troops (staff, mortarmen, radiomen, etc.) to carry. During prewar 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, bang 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 paratroop 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 handguns, while weighing half as much as the Thompson submachine gun or the M1 rifle. The U.S. Army decided that a carbine would adequately fulfill all of these requirements, but specified that the new arm should weigh no more than five pounds and have an effective range of 300 yards. Paratroopers were also added to the list of intended users and a folding-stock version would also be developed.
M1 carbine