I saw a hunting show where they were shooting bison (full grown bison, not small cows) with the .338 Federal, 185gr TTSX bullet, Using AR rifles.
One was 150 yards, one was 260, both got full penetration on the bison (broadside) and dropped the bison in short order.
It was impressive to see!
As hunters increasingly use AR's in the USA, I think that this will be a great boost for the 338 Fed, because certainly some of those guys are going to want to hunt elk and moose with their AR's and this is a way to get some real horsepower in the AR platform.