A surgical stapling system is disclosed. The surgical stapling system comprises a housing comprising a motor and a battery configured to supply power to the motor. The surgical stapling system further comprises a firing actuator operably coupled with the motor and a stapling assembly comprising a plurality of staples and a distal end. The surgical stapling system further comprises a shaft configured to support the stapling assembly, a firing member configured to transmit a firing motion from the motor to the stapling assembly, and a firing member sensor system configured to detect the position of the firing member within a detectable range of positions relative to the end of the stapling assembly.