I recall seeing a slow-motion video on YouTube of an AK-47 being fired in automatic mode, and the barrel was bouncing up and down based on the bulk of the gas piston slamming against the back of the receiver and the slamming closed again (before starting all over again). I've frequently seen articles and essays about how much cleaner and cooler the bolt in a gas piston AR is, but I've never see any comment on whether the mechanics of the gas piston affect the accuracy of the rifle. Does anyone know if a gas piston affects the accuracy of an AR?