A tool assembly comprising: an anvil assembly; a cartridge assembly movably supported in relation to the anvil assembly, the cartridge assembly including a cartridge body (424a, 424b) defining a tissue contact surface and a plurality of retention slots which open onto the tissue contact surface, the cartridge body defining a plurality of recesses, each of the recesses being associated with one of the plurality of retention slots; wherein each of the recesses has a staple magazine positioned therein and wherein each of the staple magazines includes a plurality of staples, each staple including a pair of legs and a backspan extending between the legs; each of the recesses having at least one biasing member supported adjacent each of the recesses, each at least one biasing member being positioned to urge its respective staple magazine towards its associated retention slot; and a plurality of pushers movably supported within the cartridge body between a lower position and a raised position, each of the plurality of pushers being positioned to engage and eject at least one of the staples of the staple magazine from the retention slot; wherein the at least one biasing member includes a first biasing member, wherein the first biasing member is U-shaped and includes a pair of legs supported within the cartridge body to contact the legs of a respective one of the plurality of staples in the respective staple magazine to urge the staple magazine inwardly towards a respective retention slot and said tool assembly being characterized in that the at least one biasing member further comprises a second biasing member which is supported within the cartridge body to contact the backspan of the respective staple, wherein the second biasing member is positioned to obstruct movement of the pusher from the lower position to the raised position after the plurality of staples of the staple magazine have been ejected from the respective one of the retention slots. an anvil assembly; a cartridge assembly movably supported in relation to the anvil assembly, the cartridge assembly including a cartridge body (424a, 424b) defining a tissue contact surface and a plurality of retention slots which open onto the tissue contact surface, the cartridge body defining a plurality of recesses, each of the recesses being associated with one of the plurality of retention slots; wherein each of the recesses has a staple magazine positioned therein and wherein each of the staple magazines includes a plurality of staples, each staple including a pair of legs and a backspan extending between the legs; each of the recesses having at least one biasing member supported adjacent each of the recesses, each at least one biasing member being positioned to urge its respective staple magazine towards its associated retention slot; and a plurality of pushers movably supported within the cartridge body between a lower position and a raised position, each of the plurality of pushers being positioned to engage and eject at least one of the staples of the staple magazine from the retention slot; wherein the at least one biasing member includes a first biasing member, wherein the first biasing member is U-shaped and includes a pair of legs supported within the cartridge body to contact the legs of a respective one of the plurality of staples in the respective staple magazine to urge the staple magazine inwardly towards a respective retention slot and said tool assembly being characterized in that the at least one biasing member further comprises a second biasing member which is supported within the cartridge body to contact the backspan of the respective staple, wherein the second biasing member is positioned to obstruct movement of the pusher from the lower position to the raised position after the plurality of staples of the staple magazine have been ejected from the respective one of the retention slots.