Back in the bad old days,nothing touched H205 for speed in a 338 WM;today I have a hunch RL17 seems very similar...I'd do some careful experiments along those lines.

After h205 was gone, best I've used in the 338 was RL 19 with the 225 a bit over 2900.



The 280 Remington is overbore.

The 7 Rem Mag is over bore.