Basically, it only resets the trigger faster, so that it can be depressed again. That makes firing another round faster. ANY semi-automatic weapon can be made to seem like a machine gun by utilizing this process. A "redneck" version is simply using a large rubber band. It works exactly the same. All it does is deplete your ammo faster and is not accurate. Of course, if you are firing at a herd of cows or deer, it might get more of them before they run off. I never found it to be practical. Just like most military folks will not use their weapons selector on full automatic unless they are being overrun by overwhelming numbers.