A surgical instrument comprising a handle assembly, an elongated body portion extending distally from the handle assembly, a head portion and a preload assembly is disclosed. The head portion is disposed adjacent a distal end of the elongated body portion and includes an anvil assembly and a shell assembly. The anvil assembly is movable in relation to the shell assembly between spaced and approximated positions. The preload assembly is disposed in mechanical cooperation with the shell assembly and enables longitudinal movement of the shell assembly with respect to the elongated body portion.