A surgical stapler comprising: a robotic actuating assembly, an elongate shaft wherein a proximal end of the elongate shaft is associated with the robotic actuating assembly, and a tool assembly operatively connected to a distal end of the elongate shaft, the tool assembly comprising: an anvil assembly having a bottom surface ; a channel assembly ; a staple cartridge which mechanically mounts to said channel assembly, said staple cartridge including a plurality of staples disposed therein and an upper tissue contacting surface ; a sled movable through the staple cartridge from a first position to a subsequent position to operatively force said plurality of staples from said staple cartridge to deform against said bottom surface of said anvil assembly; and a dynamic clamping member movable with said sled through said channel assembly and said anvil assembly, said dynamic clamping member having a first mechanical interface which slidingly engages said anvil and a second mechanical interface which slidingly engages said channel assembly, said first and second mechanical interfaces of said dynamic clamping member being in substantial vertical registration relative to one another to oppose the expansive forces associated with clamping and stapling tissue and to maintain a substantially uniform gap between tissue contacting surfaces of said anvil assembly and said staple cartridge during stapling, wherein said tool assembly includes a selectively movable clamping collar which biases against a cam surface on said anvil assembly to close said anvil assembly relative to said staple cartridge and clamp tissue therebetween, and said second mechanical interface of said dynamic clamping member includes a flange which secures said dynamic clamping member for translation within a corresponding slot disposed within said channel assembly upon movement of said sled. an anvil assembly having a bottom surface ; a channel assembly ; a staple cartridge which mechanically mounts to said channel assembly, said staple cartridge including a plurality of staples disposed therein and an upper tissue contacting surface ; a sled movable through the staple cartridge from a first position to a subsequent position to operatively force said plurality of staples from said staple cartridge to deform against said bottom surface of said anvil assembly; and a dynamic clamping member movable with said sled through said channel assembly and said anvil assembly, said dynamic clamping member having a first mechanical interface which slidingly engages said anvil and a second mechanical interface which slidingly engages said channel assembly, said first and second mechanical interfaces of said dynamic clamping member being in substantial vertical registration relative to one another to oppose the expansive forces associated with clamping and stapling tissue and to maintain a substantially uniform gap between tissue contacting surfaces of said anvil assembly and said staple cartridge during stapling, wherein said tool assembly includes a selectively movable clamping collar which biases against a cam surface on said anvil assembly to close said anvil assembly relative to said staple cartridge and clamp tissue therebetween, and said second mechanical interface of said dynamic clamping member includes a flange which secures said dynamic clamping member for translation within a corresponding slot disposed within said channel assembly upon movement of said sled. <EOS>