A surgical end effector (900) includes a shaft portion (901), an anvil (902) extending distally from the shaft portion, and a staple cartridge (940) comprising a plurality of staples. The surgical end effector also includes an elongate channel (911) configured to receive the staple cartridge, wherein the elongate channel is movable relative to the anvil between an open configuration and a closed configuration to capture tissue between the anvil and the staple cartridge. The surgical end effector further includes a firing member (904) configured to cause the plurality of staples to be deployed into the tissue, wherein the firing member is movable distally to positively transition the elongate channel to a closed configuration, and wherein the firing member is movable proximally to positively transition the elongate channel to the open configuration.
