An assembly for use with a surgical instrument system is disclosed which comprises a cartridge body removably positionable in a channel. The system further comprises staple cavities and a longitudinal slot defined in the cartridge body, staples positioned in the staple cavities, and pushers configured to eject the staples from the staple cavities. The system further comprises rotary drivers couplable to the pushers. The system further comprises a rotatable shaft comprising a threaded portion rotatable by a motor and, in addition, a firing member comprising a threaded aperture engaged with the rotatable shaft which is configured to displace the firing member longitudinally when the shaft is rotated. The firing member comprises a first ramp positioned on a first side of the slot configured to actuate a first row of pushers and a second ramp configured to actuate a second row of pushers disposed laterally with respect to the first ramp.
