My Proof is a 20" and I use a Rexus bolt, but 31 - 31.3 grains of LeverRevolution, 450, Lapua/AA brass, and a 120 SMK, 123 SMK, or a 123 grain SST shoot very well. That load works for me out of 3 different barrels I've used it in. Not a light load.
The Sierra 120 grain GameChanger is still...