My 180gr GK load uses 71.6gr of IMR4831 and a Win LR Primer. I get 2800fps out of it. Accuracy isn't great. I think it does 1.75" at 100 yards. That's what factory loads will do for me. I wonder if I should back off to 69.0 and work back up with magnum primers on that load?
Interestingly enough, I did another load wth 180gr Gamekings using 58.5gr of IMR4895 and a LR primer. Similar velocity, but a little better accuracy.
I tried some 150gr GK load development with IMR4895, and I got just at 1" with 3050fps out of the muzzle with me best recipe, so I'm happy with 150grain bullets.
I picked up a box of 200gr Gamekings to see what a heavier bullet would do in my rifle. H1000 is touted as being a good powder for the .300WM with heavier bullets, but I wanted to see what others here thought. I think I will use the LRM primers in my load development.