Gun History: Reising Submachine Guns

The Thompson and the Grease Gun are well known submachine guns used by the Allies during WWII. The Reising Models 50 and 55 aren’t as well known but fulfilled a gap for the U.S. Marine Corps and Navy. It fires the .45 ACP cartridge at a rate if between 450 and 500 rounds a minute. It was designed and patented by Eugene Reising in 1940. During WWII around 100,000 Reisings were produced, although exact numbers aren’t available.

The Reising isn’t a true submachine gun. It is a selective fire weapon and can be fired as a semi-automatic carbine or as a fully automatic machine pistol. The Reising was easy to produce and had a huge cost advantage over the Thompson. Mass produced Thompsons cost the military $225 per weapon while the Reising only cost $50 per unit.

Unlike most submachine guns from WWII, the Reising is a delayed blowback weapon that fires from a closed bolt. The bolt locks into position by rising slightly into a recess machined into the top of the receiver. Most submachine guns used the conventional blowback method of operation and fired from an open bolt that allowed for simple operations and better cooling of the chamber. The major disadvantage of the blowback method was the fact that the heavy bolt slammed forward almost simultaneous to the moment of firing, disturbing aim. The Reising fired from a closed bolt which greatly increased accuracy over the open bolt. The open bolt method of firing allows for quicker cooling but Reising believed that accurate fire was more important than cooling.

The U.S. Marines stated using the Reising in 1940. Each division was given 4,200 with around 500 being issued to each infantry regiment. At first Reisings were issued to officers and NCOs because of a lack of M1 Carbines. While Thompsons were available to the Marines, the jungle fighting of the Pacific theatre made the Reising the submachine gun of choice. The Thompson was too heavy and bulky for arduous patrols.

The Reising worked fine in training when it could be cleaned often. But because of the tight design there was little tolerance for dirt, sand and mud. Under the combat conditions of jungle warfare the Reising didn’t come close to matching the Thompson. If it wasn’t continually cleaned it would misfire at an alarming rate, putting a marine’s life at risk.

By late 1943, the Reising was withdrawn from the Fleet Marine Force. By this time the M1 Carbine was more available. Reisings were given to the OSS for clandestine operations behind enemy lines. Some were also purchased by Canada and saw frontline service overseas.  Many consider the Reising the worst small arms produced by the United States but it is historically significant because of its utilization during the early stages of the Pacific War.