text: how do machine guns work? recoil systems blowback system gas system the recoil system uses the energy of the newtonian reaction to load and fire the next round, most automatic pistols use this method. gas and blowback are one in the same. they use the pressure of the gas int the chamber to reload and fire. most fully automatic weapons use this method. the more advanced and the first machine gun(gattling) use a mechanical powered drive sytem to reload and fire.