A surgical stapling instrument (10) comprising a handle assembly (12) having a proximal end, an elongated body portion (14) extending distally from the handle assembly, a head portion (16) disposed adjacent a distal portion of the elongated body portion and including an anvil assembly (30) and a shell assembly (31). The shell assembly includes a shell and a staple guide (60) housing a plurality of staples (70). A flexible engagement structure (80) attaches the staple guide to the shell.
