7 RM. I have worked up loads on 5 different 7 PRC's this year and I am not impressed with there performance for the the amount of powder they burn. My Saums run close to the same velocity with 5 grains less powder ! I have had several 7 mags that would easily out run the prc. I reload all my ammo, but the factory stuff I did try in the 7 prc was really a turd.