The L7 Bolt System Upgrade for the DM4 takes accuracy, speed, and efficiency to a whole new level. The idea behind the L7 Bolt System is to reduce the moving mass inside the marker to the bare minimum. Lightening the bolt means that the marker will naturally have less kick/recoil and take less pressure and time to move the bolt back and forth. This means your marker will produce less vibration and recoil with each shot. This in turn allows you to stay on target better ....hence shoot more of your opponents.