Woody, I haven't tried the magnum primer (yet) with the .308 and WC846, but I did with W748. In my rifle, a Browning Abolt, the WLR primer worked better than CCI magnum primers. The groups were a bit larger, and I had a pretty large spread in velocities. This isn't to say your experiences might not be different. I too have seen many recommendations to use mag primers with ball powder, and this may be a fluke of my rifle and the particular loads I tried. I plan to investigate further, but haven't really done much with the WC846 and .308 yet.
My final plan is to see which powder works best in both calibers order more of that one, keeping it simple. As long as it works really well in the .223 and at least "pretty good" in the .308, I'll be happy, since I've always used, and will continue to do so, RL15 for my hunting loads in .308. The military powders and FMJ bullets sure make practicing with the .308 economical.
Good shooting.