Thompson Sub-machine gun 'Tommy Gun', invented in 1919. The Thompson was favored by soldiers, criminals, police and civilians alike for its ergonomics, compactness, large .45 ACP cartridge, reliability, and high volume of automatic fire.
George "Machine Gun" Kelly is probably considered one of the most famous "gangsters" from the prohibition era. "Machine Gun" was born George Kelly Barnes on July 18, 1895, to a wealthy family living in Memphis, Tennessee. His nickname came from his favorite weapon, a Thompson submachine gun. Kelly’s most famous crime was the kidnapping of oil tycoon & businessman Charles Urschel in July 1933 for which he, and his gang, earned 200,000 dollars ransom.
Winston Churchill squints as he test fires an American M1928 Thompson submachine gun, many of which were supplied to England under the Lend-Lease program. Note the unusual hybrid forestock with both descending pistol and horizontal hand grips.