Disclosed is a surgical stapling apparatus comprising: a) a handle assembly including a movable handle, the movable handle being movable through an actuation stroke; b) an elongated body extending distally from the handle assembly and defining a longitudinal axis; c) a tool assembly pivotably mounted adjacent the distal end of the elongate body, the tool assembly having a cartridge assembly and an anvil assembly; d) an actuation shaft supported at least in part within the handle assembly and mounted for longitudinal movement in response to manipulation of the actuation handle; e) an articulation mechanism including an articulation lever mounted adjacent the handle assembly and an articulation link, the articulation link having a proximal end operatively connected to the articulation lever and a distal end positioned adjacent the distal end of the elongated body; and f) a drive assembly having a drive beam including a plurality of sheets.