A surgical stapling instrument, comprising: a shaft; a plurality of staple cartridges positioned within said shaft, wherein each said staple cartridge comprises: a cartridge body comprising a plurality of apertures; and a plurality of staples each comprising a staple leg positioned in a said aperture, wherein said staple legs are slidable within said apertures; a first jaw comprising a channel configured to receive one of said staple cartridges; a second jaw comprising an anvil, wherein said staple legs are configured to contact said anvil; a cartridge driver configured to sequentially advance said staple cartridges into said channel; and a firing member configured to be moved along a firing path, wherein said firing path comprises: a proximal position in which said firing member is displaced in a transverse direction with respect to said firing path, wherein one of said staple cartridges can slide past said firing member when said firing member is displaced in said transverse direction; and a plurality of firing positions in which said firing member drives said staples against said anvil, wherein either: the shaft further comprises a frame and the firing member is in contact with the frame when the firing member is in the proximal position and is displaced in said transverse direction with respect to said firing path; or the first jaw comprises a displacing cam and the firing member is in contact with said displacing cam when the firing member is in the proximal position and is displaced in said transverse direction with respect to said firing path. a shaft; a plurality of staple cartridges positioned within said shaft, wherein each said staple cartridge comprises: a cartridge body comprising a plurality of apertures; and a plurality of staples each comprising a staple leg positioned in a said aperture, wherein said staple legs are slidable within said apertures; a cartridge body comprising a plurality of apertures; and a plurality of staples each comprising a staple leg positioned in a said aperture, wherein said staple legs are slidable within said apertures; a first jaw comprising a channel configured to receive one of said staple cartridges; a second jaw comprising an anvil, wherein said staple legs are configured to contact said anvil; a cartridge driver configured to sequentially advance said staple cartridges into said channel; and a firing member configured to be moved along a firing path, wherein said firing path comprises: a proximal position in which said firing member is displaced in a transverse direction with respect to said firing path, wherein one of said staple cartridges can slide past said firing member when said firing member is displaced in said transverse direction; and a plurality of firing positions in which said firing member drives said staples against said anvil, a proximal position in which said firing member is displaced in a transverse direction with respect to said firing path, wherein one of said staple cartridges can slide past said firing member when said firing member is displaced in said transverse direction; and a plurality of firing positions in which said firing member drives said staples against said anvil, the shaft further comprises a frame and the firing member is in contact with the frame when the firing member is in the proximal position and is displaced in said transverse direction with respect to said firing path; or the first jaw comprises a displacing cam and the firing member is in contact with said displacing cam when the firing member is in the proximal position and is displaced in said transverse direction with respect to said firing path.