Work up to 55 gr. RL 15 or IMR 4064 both will do a good job with that bullet at 2900 fps you can go more but work up slowly. Varget is another good powder.I have worked up to 3000 fps chrono'd without signs of pressure but I think that is to fast for the bullets construction.
Our load book says Viht N150 was the most accurate load in our test barrel for the .338-06 180gr Ballistic Tip. 53.5 gr starting point, 55 most accurate load, 57 max load. As always start low and watch for pressure signs.
