A staple cartridge insertable into a surgical stapling instrument is disclosed. The staple cartridge comprises a threaded rod and a firing member configured to move from a proximal unfired position toward a distal position as the threaded rod is rotated in a first direction. The firing member comprises a first portion comprising a first camming member, wherein an anvil of the surgical stapling instrument receives the first portion when the firing member in the proximal unfired position and a second portion comprising a second camming member, wherein a staple cartridge jaw of the surgical stapling instrument receives the second portion when the firing member is in the proximal unfired position, and wherein the first portion and the second portion are configured to maintain a distance between the anvil and the staple cartridge jaw during a staple firing stroke.
