It’s possibly true the .338 Fed and .338-06 don’t do anything a .30-06 can’t do, but who cares?
I’ve shot a bunch of critters on two continents with the .338 Win Mag, and this year I’ll be hunting with a 6 1/4 pound (with scope) .338-06. Why not?
The last 6 mule deer I killed were taken with .308, 7mm-08, .257 Roberts, .257 Weatherby. .270 Winchester, and .284 Win.
This year I hope the little.338-06 gets an elk and mule deer.
I left behind the “this cartridge is better than that one” silliness about 25 years ago. Now I pick rifles and cartridges because they seem fun, interesting, different, or have a connection for me.
A good bullet in the right place ends the discussion.