First upload didnt show the technique and now I dont know how to edit the item. This shows the actual technique.  Interesting technique for bump firing from the shoulder. Albeit an incredible waste of money, it can be fun and is legal as the trigger is manipulated once per round and does not fall under the NFA. "Bump firing is the act of using the recoil of a firearm to fire multiple shots in More.. rapid succession. This process involves holding the foregrip with the non-trigger hand, releasing the grip on the More..firing hand (leaving the trigger finger in its normal position), pushing the rifle forward in order to apply pressure on the trigger finger from the trigger, and keeping the trigger finger stationary. The firearm will recoil and then return to its previous position after the round has been fired first resetting and then pressing forward against the trigger thereby firing successive shots. The rapid bursts from semi-automatic firearms simulate the discharge of automatic firearms. Even though a large number of rounds are fired in rapid succession, the trigger finger initiates each discharge; therefore, fully automatic fire is not actually taking place."