That link I put up is for a Staghorn breech plug. They are a single unit with the primer going into the breech plug. Whether you would need a different hammer I could not say. I would suggest giving CVA/BPI a phone call. They would be able to help you out. Since the Staghorn is no longer produced, they might be your only source for parts. The Buckhorn Magnum took the place of the Staghorn as I understand it.