Shot my first deer of the season a week ago with my 300 WSM using Fusion 165 gr ammo, and it didn't dissapoint at all.
Bullet expansion was very good, and I hit my deer with a passthrough shot right behind the shoulder. It ran 20 feet and then hit the ground dead as a doornail.
I honestly planned to handload for this gun using nosler bullets, but the accuracy is outstanding as is the killing power. I may not bother.
I'm sure it'll work good in your 338 as well.