I picked a load last year oin my 300WSM, which was very accurate, but lackign in velocity for the cartridge- abotu 2950fps.
I used H4831 and 168gr TSX
I got pressure signs a littl etoo early, but of course my rang ework up with 7 differnet loads you coudl cover with a quarter....
As soon as I have time, I will be trying a bunch of other stuff.
I have also found that soem of the really slower powders work very well, like R22, RL 25.
Everyone seems to be jumping at 4350 and RL19 for this cartridge, but I wonder why sometimes....It's got a similar case capacity to the 300WM (a little less) and the 7RM and those cartridges seem to relaly liek the slooow powders.
I intend to try out IMR 7828 SC soon. One way or the other, it's going to end up with 7828, 4350 or 4831, since the Alliant (RL) powders are harder to get rigth now for some reason, and they are 30% more $$$ it seems!