In mine with a 165 bt I use 72 gr of IMR 4350 and with a 180 Hornady bt I use 70 gr of same powder with either a Rem 9 1/2 or 9 1/2M primer in either WW or Rem cases. No problems with pressure and both are accurate.
mine shoots best at or very near maximum loads..165 gr sierras behind 77gr of IMR 4831 shoots 3 shot groups you can cover with a quarter..any day of the year. WORK YOUR WAY UP TO THAT LOAD!!!!!!!!..it is a MAX load..hot!!..
Of all the different combos I've tried ( and I load for 4 different .300 Win Mags) the most consistenly accurate deer load is a 180 gr. Speer Grand Slam over a book max charge of IMR-4350. Runs around 3050 fps and the Speer GS ALWAYS holds together and puts two holes in a deer.