A surgical stapling and severing instrument particularly suited to endoscopic procedures incorporates a handle that produces separate closing and firing motions to actuate an end effector. In particular, the handle produces multiple firing strokes in order to reduce the required amount of force required to fire (i.e., staple and sever) the end effector. A flexible rack transmits these firing strokes to a firing rod that reciprocates in an elongate shaft to actuate the end effector. The flexible rack advantageously stows into a pistol grip of the handle when retracted to minimize handle length.