Two years later he submitted his completed design to the Harrington & Richardson Arms Company (H&R) in Worcester, Massachusetts. It was accepted, and in March 1941, H&R started manufacturing the Model 50 full stocked submachine gun. Months later, production began on the Model 55 (identical to the Model 50 other than having a folding wire buttstock, no compensator, and a barrel half an inch shorter); and the Model 60 full stocked semiautomatic rifle that also resembled a Model 50, but had a 7.75 inch longer barrel without cooling fins or compensator.