The Marines used the guns during the Banana Wars. In 1926 he got orders from the United States Postal Service and the United States Marine Corps. He tried selling it in the US but sales were slow. General Thompson tried to sell his gun to European countries with little success. This model weighed 10.25 pounds (4.65 kg) and had an effective range (distance it was accurate) of 164 feet (50 m). In 1921, the Colt Patent Firearms Company made 15,000 Thompson submachine guns for Auto-Ordinance at a cost of $38.25 each.
In 1921 the first model, called the M1921, was produced. Thompson and Auto-Ordnance began developing the gun for civilian markets. The first cases of the new submachine gun arrived on the docks for shipment on Novemthe same day the war ended. Designed for use in World War I, the gun was first called "The Annihilator I" (Thompson nicknamed it a trench broom) could fire 20 rounds per second. In 1916 Auto-Ordnance was started with Thompson holding the majority of shares. These were the M1903 Springfield rifle and the M1911 pistol. He later played a part in developing two important American military weapons. This was at a time of almost complete chaos in the army supply system. During the Spanish–American War he made a reputation for himself making sure ammunition got to the front lines. Capacity: 20/30 round stick magazines 50/100 drum magazines.Operation: friction delayed gas blowback.