The Rossi front sight was used to make the filler. The tail cut off, trimmed .48 inches long and flattened on the underside. A snug push fit with the thumb. Once the groove and sight tail were cleaned, they were painted with 609 locking compound and pressed back into place. 609 was flooded over the top and allowed to wick into the joints. The excess wiped off. Upon hardening, it expanded into the joints locking the new serrated filler into place. It takes about 350 to 500F (soldering iron works) to break the bond so it should stay in place nicely. Could also drill and pin or use epoxy or solder into place. Could even just fill the mortise with black colored epoxy. IF it pops out I'll holler back.....don't think it will though.