My 2 cents. I have two very accurate 308 rifles (Accuracy International) . The second one I bought comes from the factory set up for small rifle primer brass. So I use Lapua LRP brass in one and SRP brass in the other. So far I have found no difference in performance. The SRP brass takes ,1gr less of Varget to get same velocity.I load 185gr Berger Juggernauts at 2650 fps.I shoot all winter (in Canada, to boot!) and down to 5 below zero I've seen ignition issues and the velocities in both rifles continue to be the same.