A reload assembly includes a shell housing, a staple cartridge, a staple actuator, and a knife carrier. In embodiments, the knife carrier or the shell housing defines a locking groove and the other of the knife carrier and the shell housing supports a locking member. In other embodiments, the knife carrier or the staple actuator defines a locking groove and the other of the knife carrier and the staple actuator supports a locking member. The locking member is received within and movable through the locking groove to prevent readvancement of the knife carrier after the reload assembly is fired.