A surgical stapler for use during an open hernia repair comprises an elongated shaft having a handle at its proximal end and a downwardly disposed staple discharge head at its distal end. A squeeze trigger on the handle is operable to cause a supply of staples to be selectively discharged from the port. One or more mesh manipulators are provided on the head and serve to assist in positioning or otherwise manipulating surgical mesh prior to fixation with the staples. In one form, the stapler includes a chamfered portion, a cantilevered portion, and a retention lip to prevent multiple staples from deploying after a single pull of the trigger. Further, in this form, the stapler prevents incomplete staple formation if side load forces are applied during insertion of a staple in tissue thereby reducing waste of staples.