When I hunted elk, I used a .338 Win Mag with Nosler partition bullets, mostly the 250-grain.
My brother-in-law usually hunted with me and used a .280 Remington and various factory-loaded ammo. He killed his elk just as dead with the .280 as I did with the .338 Win Mag.
That being said, I'd rather use a .280 Remington for elk hunting than a .338 Federal because, as other posters have noted, the .280 will shoot flatter at the longer ranges.
