The Thompson Light Rifle was an attempt by Auto-Ordnance to manufacture a light rifle for the US Armed Forces. The overall weapon was based on their well proven .45 ACP submachine gun although the first prototype actually was based on the M1921 and it almost resembles the MG42. The only major differences from the SMG was the barrel shroud, pressed steel components to ease production/reduce weight and the inlined stock reduced barrel climb improving accuracy. The Thompson Light Rifle was more reliable and accurate than the M1 Carbine that was adopted and also came with the capability of select fire, which made it close to the likes of the STG-44 despite the round it used.