The Thompson submachine gun is an American icon, becoming famous during the Prohibition era when it was a common sight of the time. Used by both law enforcement officers and criminals, it was also known as "Tommy Gun", "Chopper", "Chicago Typewriter", "The Trench Broom" and "Chicago Piano". The Thompson was favored by soldiers and civilians alike for its compactness, large .45 ACP cartridge, and high volume of automatic fire. The M3 is an American .45 caliber submachine gun that uses the .45 ACP (11.43x23mm ACP) pistol cartridge, most commonly referred to as a grease gun, owing to its similarity in appearance to the common mechanic's tool. It entered US Army service on December 12, 1942 as the United States Submachine Gun, Cal. .45, M3 and began to replace the .45 caliber Thompson series submachine guns: the M1928A1, M1 and M1A1 that were slowly being withdrawn from use. The weapon’s designer was G. Hyde, while F. Sampson – GMC’s Inland Division chief engineer – was responsible for preparing and organizing production. Even at the development stage, the weapon’s design was focused on simplified production, ease of use and the ability to convert the weapon to the 9x19mm Parabellum pistol cartridge. The Reising was an American submachine gun patented in 1940 and manufactured by Harrington & Richardson. It was designed by Eugene Reising in 1940. The two versions of the weapon produced during World War II were the M50 and the simplified folding-stock M55. Over 100,000 guns were ordered, and were initially used by the United States Navy and Marine Corps, though some went to Canadian, Soviet, and other armies. New .45 rifles on the scene gaining much attention are the "Henry Big Boy", used in the sport of Cowboy Action Shooting, and the .45 Beretta Storm, which is becoming a popular sport/home defense weapon.