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.