If your building a dedicated target rifle for long range and wanted extreme barrel life, the 338 WSM would be a good choice with a 300 gr SMK but for game its velocity would be pretty limited even in a long barreled rifle.
A better choice would be the new Wildcat 265 gr AL RBBT when its ready for production. Offers BC way over the 300 gr SMK and also offers around 125 to 150 fps more velocity. Would be a very good choice for such a round.
I have an XP-100 in this chambering but I used a 1-12 twist Lilja 15" barrel as I was only interested in shooting bullets of 225 and under. It performs extremely well. 180 gr BT at 2950 fps, 200 gr BT at 2800 fps and a 225 gr at around 2700 fps if I run her pretty good. All out of a 15" barrel!!!
She will do better then 2500 fps with the 250 gr SMK I would imagine in a rifle length barrel. In fact from what I have seen, it will run within 50 to 75 fps of the 338 Win Mag and in most 24 to 26" barreled rifles the Win Mag will push near 2700 fps with a 250 gr SMK.
Again, if your looking for paper punching or target type shooting it would be great with an extreme barrel life for its performance level. But if your looking for big game hunting at long range, there would be much better bullet choices then the 250 and 300 gr SMK. Again the aluminum tipped Wildcat bullets may just be the perfect choice for this class of round to boost their terminal performance on big game at long range. More testing to come very soon.
I will be testing these bullets on an early season elk hunt here at the end of the month in my 338 AX so a report will come soon after.
Kirby Allen(50)