“Military science develops so fast in times of actual war which the weapons of currently soon is (sic) discarded and something improved taken up.” The accurate progenitor of recent machine guns was the Maxim gun, invented by American-British inventor Hiram Maxim in 1884. Maxim‘s style made use of the recoil https://machguns.com/product/lot-1450-auto-ordnance-a-range-1928-thompson-class-iii-nfa/