The Hyde-Inland M2 was the highest-rate United States submachine gun design submitted for trials at Aberdeen Proving Ground in February, 1941. Work was undertaken by General Motors Inland Manufacturing Division to develop workable prototypes of George Hyde's design. The design was designated U.S. Submachinegun, Caliber .45, M2 as a substitute standard for the M1 submachine gun in April, 1942. As Inland's manufacturing capacity became focused on M1 carbine production, the US Army contracted M2 production to Marlin Firearms in July, 1942. Marlin began production in May 1943; but Marlin's original contract for 164,450 M2s was canceled in 1943 upon adoption of the M3 submachine gun. The M2 is chambered for the .45 ACP cartridge and used the same 20- or 30-round magazine as the Thompson. Its cyclic rate of fire is 525 rounds per minute. Only 400 at the most were manufactured and none were issued by any branches of the United States military.
The M2 is a simple blowback operated design, although it was difficult to make. The receiver was built from a steel forging and a seamless tubular section, which took extra time and effort to machine and finish, causing the US Army to adopt the M3, instead. The bolt was shaped unusually, having a large diameter at the rear, and being slender in the front. Unlike the M3 it had a fixed wooden stock, and wooden furniture.