Super convenient and safe dry firing of M1A / M14 and M1 Garand rifles. Drop in device positively prevents firing while a 1/4" tug on the op rod rests the trigger for the next shot. No more M1 thumb and breaking position to reset the trigger. Eliminates impact damage to firing pin tail and acts as an Open Bolt Indicator. Improves trigger technique and follow through. Makes dry-firing fun.