Ram Priming Unit by RCBS RELOADING PRODUCTSThe positive Ram Priming Unit gives you better “feel†by seating the primer at the top of the press stroke. You can also pre-set a positive stop to speed up your loading process. Works with any press with a 7/8 x 14†thread and RCBS-type and removable Shell Holder. Includes primer rod assemblies for all rifle and pistol Boxer-type primers.