Congratulations on the new shooting iron and Happy New Year!
I've been using a .338 Winchester Mag. (Winchester Model 70 Stainless) for approximately 15 years and have tried all sorts of bullet/powder combinations.
For hunting, I got great results with the old blue-coated Barnes 210 gr. XLC bullets and a lot of IMR4350 powder in Remington nickel-plated brass, using Federal 215 primers.
I am currently developing a load for Hornady 225 Interbond bullets and by far, the most promising powder has been Reloder 19, using the same other components. Velocity topped at 2980 fps with a load that will be over maximum in some other rifles, but safe in mine. I still lowered the charge by 1 grain, to be on the safe side to produce 2950 fps. Since my rifle has a BOSS muzzle brake
/tuner, I now have to toy around with the setting that will give me the best 3-shot groups at 300 meters. Realistically, if you can get a group measuring les than 1.5 inches at 300 meters out of a hunting rifle with a sporter countour barrel, you cannot complain. Just my humble opinion...