U.S. General Motors - Guide Lamp Division (Detroit, MI) M3 Submachine Gun

Approximately 650,000 M3 and M3A1 Submachine Guns were manufactured by GM's Guide Lamp Division during the Second World War, including 1,000 for use by the O.S.S. An additional 33,000 M3A1s were produced by the Ithaca Gun Co. during the Korean War. The M3A1 included several modifications to correct deficiencies in the original design. Among these are a larger ejection port, elimination of the retracting handle and substitution of a finger hole for use in cocking the gun, and the addition of a guard for the magazine catch.

Machine guns have their roots in the multi-barreled Gatling guns of the Civil War and Indian Wars period. These mechanically-operated arms were superseded by a true machine gun in the modern sense, when Hiram Maxim developed a fully-automatic gun early in the 20th century. These large, cumbersome crew-served arms were widely used during the First World War, and some believed that they were so terrible and fearsome that they would make the concept of war obsolete. Before that conflict had reached its conclusion, Germany had produced the first "submachine gun," a small fully-automatic rifle that chambered a pistol-class cartridge. The 9mm caliber Bergmann Maschinen Pistole18, also known as the Kugelspritz, or "bullet squirter," was the forerunner of other such arms, including the famous German MP38 and MP40 "Schmeisser," the 7.92mm caliber Sturmgewehr, the British Sten, and Soviet PPSh, all of which were widely used during the Second World War. American troops were also equipped with submachine guns, perhaps the best known of which is the Thompson, which was designed shortly after the end of the Great War. Although these arms performed yeoman service in all theaters with both American and Allied troops, the search was underway for a replacement arm even before the United States became actively involved in combat. Both U.S.- and foreign-designed submachine guns were submitted for testing by Army ordnance officers, where the all-metal Sten, consisting largely of stamped and welded components, made a surprisingly good showing. Although extremely crude when compared to the milled-and-machined Thompson, the British entry proved to be extremely inexpensive to produce while maintaining accuracy, reliability, and other features desirable in a combat arm. American designer George Hyde's submission featured a wood stock, pistol grip, and stick magazine similar to those of the Thompson, but his design was much less expensive to produce than the Auto-Ordnance arm. The Army contracted with the Inland Manufacturing Division of General Motors to refine Hyde's design, which was adopted in early 1942 under the designation "U.S. Submachine Gun, Caliber .45, M2." The M2 never entered production due to defense requirements for other types of arms, coupled with a lack of available raw materials. The Army began once again to search for a suitable replacement for the Thompson. Ordnance Department specifications required that the new gun be of all-metal construction, with stamped components used where possible to decrease costs and simplify production. George Hyde returned the drawing board and later produced a new design that met the Army's requirements. Included were a pistol grip, a collapsible wire butt stock, a pivoting frame-mounted operating handle, and a 30-round stick magazine. The construction of this gun was much simpler and less expensive than the Thompson, and at a manufacturing cost of about $20 each, they provided a substantial savings to the government over the purchase of other combat arms. As with the M1911 pistol, its generous tolerances ensured proper operation even when dirty. This feature, along with the use of two bolt guide rods and the inclusion of an ejection port cover which aided in keeping dirt out of the mechanism, contributed to a high degree of reliability. Hyde's design also featured a low cyclic rate of fire which combined with its straight-back recoil to make the gun easier to shoot while eliminating the muzzle's tendency to climb under fully-automatic fire, a common trait in other submachine guns. Adopted by the Army in December 1942 as the "Submachine Gun, Caliber .45, M3," these guns were manufactured by the Guide Lamp Division of General Motors. Production began early in 1943, and the first versions reached the front lines later that year. The M3's unusual profile, stamped frame and receiver, and all-metal construction were vastly different from anything previously seen in the U.S. arsenal, and soldiers quickly dubbed it the "Grease Gun." Their light weight and compact size made them ideal for tank crews and airborne troops, and it was with these units that the M3 was first used in combat. After later adoption by the Marine Corps, these arms also saw action in the Pacific island campaigns. A 9mm conversion kit, consisting of a new bolt, magazine, and barrel, was also produced to allow O.S.S. and other covert units operating behind the Nazi lines to make use of captured German ammunition. Combat use revealed some weaknesses in the M3's design, and early in 1944, changes were made to improve the operating lever and to strengthen the magazine catch and rear sight. A second round of changes later in the year eliminated the operating lever completely, replacing it with a finger hole which made it possible to cock the bolt. The ejection port was enlarged, a guard was provided for the magazine catch to prevent accidental releases, and the collapsible butt stock was re-contoured to allow it to function as both as a magazine loading tool and as a barrel wrench. These modifications, along with some additional minor changes, led to a December 1944 re-designation of new production guns having these improvements as the M3A1. Shortly before Germany's collapse, the M3 and M3A1 officially replaced the Thompson as the Army's standard submachine gun, but the war ended before the latter gun was withdrawn from service. Over 600,000 M3s were produced during the Second World War, while only about 15,000 M3A1s had rolled out of Detroit before the end of hostilities. Although these arms were produced exclusively by Guide Lamp, the Ithaca Gun Co. manufactured the M3A1 during the early 1950s. These submachine guns also served with American troops in Korea and Vietnam, and many were provided to the armed forces of U.S. allies. The M3 and M3A1 mark a watershed in U.S. military thinking with respect to small arms. Due to the exigencies of war, the production of more costly, finely-made guns began to yield to arms that could be produced quickly and inexpensively. This philosophy continues today with the extensive use of polymers and alloys in the construction of the M16 battle rifle and the Beretta M9 and Heckler & Koch Mark 23 SOCOM pistols. Even with the improved technologies and manufacturing techniques represented in modern combat arms, the guns that inaugurated these changes in the U.S. military may still be found in service over fifty years after their introduction.