The Machinenpistole 5 designed by the German manufacturer Heckler & Koch in the mid-1960s is the basis for the new Military Armament Corporation large-format, roller-delayed blowback pistol in 9 mm.

The gun uses a delayed blowback action, with the shooter’s finger pressure on the trigger acting as the delaying force – not exactly an ideal system! In Austrian trials (which were the only ...