Origin: USA
Year: 1921
Type: Submachine gun
Caliber: .45 ACP
Weight: 10.8 lb (4.9 kg)
Length: 33.7 in (860 mm)
Barrel length: 10.52 in (267 mm)
Capacity: 50 rds (20 rd and 30 rd stick mags and 100 drums also available)

Developed by General John T. Thompson, the Thompson submachine gun was originally conceived a means of greatly increasing the firepower of an individual soldier on the battlefield. This was especially important as World War One saw the use of trench warfare and Thompson believed his submachine gun design would proved valuable as a "trench broom" capable of sweeping trenches clean of enemy troops. Unfortunately for Gen. Thompson and his company Auto-Ordnance, the first prototypes of the new weapon arrived too late for the war and the US and other militaries showed little interest. Furthering hindering potential sales was the high cost of the gun at $200 for a basic model with a 20 round magazine in 1921, (~$2,800 today). However, Thompson did secure some sales of his first production model, the M1921. A small number were purchased by the US Postal Service and the US Marine Corps. Gangsters and lawmen alike also acquired the "Tommy Gun" and used them to great effect throughout the 1920s. However, the first major purchaser of the M1921 was the Irish Republic Army which purchased several hundred of the guns. Though most were seized by US customs agents in New York, many of the guns made their way to Ireland and saw service in the Irish War of Independence and Irish Civil War and continued to turn up in the Troubles later in the century. Despite being invented too late and at too high of a price, the Thompson submachine gun still managed to become a highly successful weapon and an icon of the Roaring Twenties.