For primers, stick with the WLRM. I never tried the 225 grain in mine, but had excellent success with the 200 grain Hornady, 250 grain Hornady and the 275 grain Speer. I found a light load in the 200 grain that would shoot a ragged hole all day. As the charge was increased, the group opened up, until I got it hot, then, it tightened right up again. The 250 grain wouldn't shoot worth a hoot, until I got it hot as well. Same for the 275 grain. I found IMR 4831 to be excellent for the 338.