brasskeeper,
I have found that I get the best velocity using IMR 4831 in my .338. I'm getting 2880 fps. with a 225 grn. Nosler Partition. Each rifle is an individual, and your results may vary considerably. Any weight of the Nosler Partition bullets are good choices, as are the Barnes bullets, although my rifle did not like them.
Try some of the "tried and true" varieties in your rifle to see what shoots best in it. Power is not an issue with a .338. It is an Elk slammer!
Best of luck, and enjoy!