Abstract: An improved tuck pointing gun for repairing masonry structures and the like is provided which includes an elongated, tubular, mortar-receiving barrel, along with an improved, axially shiftable plunger within the barrel which is selectively shiftable therein through the usual ratchet rod and trigger mechanism associated with such guns. The plunger includes a thin, flat, circular, metallic plate having an annular, flexible member coupled thereto. The flexible member includes a forward beveled lip, a radially restricted portion at the region of the plate, and a rearwardly and outwardly extending annular trailing section which engages the barrel wall.