Try both but your rifle will tell you what it prefers.I'veshot both, my old Omega referred the .44's and my Black Diamond Xr loves the .45's.With the non-mag and mag versions in .45 caliber, you have a more versatile choice in bullets. If you like lighter loads shoot the non-mags. If you like the shoulder artillery go with the mags.Cant really go far wrong with an XTP!