I've used 75 grains of IMR4350 with a CCI 250 Magnum primer in Winchester cases behind the Nosler 210 grain Partition bullets as a hunting load for many years in my pre-64 Model 70 "Alaskan" Winchester with it's 26" barrel. It's a "stout" load, but reasonably accurate and very hard-hitting with the above bullets at 3,020 fps.
Lately, I have also reloaded and shot some 200 grain Nosler Ballistic Tips using the same load and found that load reasonably accurate as well at 3,064 fps.
However, this load may NOT be safe in your rifle, so "work up" to this load with caution.
Good luck with your .338 Win. Mag... it's a fine caliber that can easily take any North American big game as long as you can take it's considerable recoil.
Strength & Honor...
Ron T.