I like H1000 in the .300 WM. 168 to 200 grain bullets.
My most accurate load (which I sent in for the dials was with 78.5 gr of H1000, 190 gr Berger, and WLR primers. I am only getting 2930 fps or so, but it was accurate so I stayed with that load.
I had a real accurate load worked up before with 168 gr TSX but thought I'd try the Bergers this year. Bergers turned out to be a little bit more accurate. I can't remember for sure off the top of my head now, but I think I was using 81.0 gr of H1000 and around 3200 fps with the Barnes.
(I should add, I'm not using the 190 gr Bergers on elk. If I were elk hunting, I'd probably go back the 168gr TSX load or 180 gr Nosler Accubond).
Nosler has some good reloading data these days:
http://load-data.nosler.com/load-data/300-winchester-magnum/