A method for controlling a powered surgical stapler that includes an end effector with jaws that are movable between an open and a closed position and a firing member that is movable between a starting position and an ending position within the end effector. The jaws and firing member are controlled by separate rotary systems and the end effector includes a firing member lockout system that prevents axial movement of the firing member unless the surgical staple cartridge is in ready to fire condition.