You are barking up the wrong tree on this one. That powder is WAAAAAAAAAAY TOO SLOW to work in the .338 Win Mag, which does its best work with powders more appropriate to the 30-06.
Unless you are loading for a .50 BMG or a smaller chambering that is HUGELY overbore, US869 isn't going to work. It is just about the slowest powder in existence:
Your best bet is to sell it to a .50 cal shooter or try to trade it for a couple pounds of H4350, H4831, or RL-19.