Abstract: A primer pocket swaging device for use in cartridge reloading equipment, which is characterized by a cylindrically-shaped collet cover having a hollow, threaded interior for receiving a threaded nipple to enclose an expandable collet. The collet includes four shaped collet segments fitted together in expandable relationship by means of an O-ring and one end of a punch rod projects through the collet and the opposite end seats on the plunger of the reloading equipment by operation of a rod lock nut and an adaptor. The upper end of the collet cover is bevelled and fitted with an opening to receive the base end of an empty shell casing, wherein the base of the shell casing is inserted in the opening and is momentarily seated and held in the collet, while the punch rod extends upwardly and swages the empty primer pocket in the casing base responsive to operation of the reloading apparatus.