A surgical instrument including a handle assembly, an elongated portion, an end effector, and a stop member is disclosed. The end effector is disposed adjacent a distal portion of the elongated portion and includes a first jaw member and a second jaw member. At least one jaw member is movable with respect to the other jaw member between spaced and approximated positions. The first jaw member includes an upper tissue-contacting surface and a lower shelf portion. The shelf portion includes a groove disposed therein. The stop member is disposed adjacent a distal portion of the first jaw member and is pivotable with respect to the first jaw member between a first position, a significant portion of the stop member being positioned external to the first jaw member, and a second position where a lower portion of the stop member being positioned at least partially within the groove.