The Reising also used a 20 round magazine too. Eugene Reising designed this smg before WW2, H&R produced around 100,000 by 1945, both the Model 50 with the wooden stock and the Model 55 with the wire folding stock, most of the production going to the USMC. The Reising fired both semi and full auto from a closed bolt and used a bolt retarding mechanism. The Reising was not a sucessful military weapon, but was better used as a Police or plant guard weapon, there weren't enough Thompsons available.