A ton of overkill beats an ounce of underkill.
Did someone mention elk in thick timber? There were four elk in the photo below as I recall. Even though I took the pic I can only find two, both of them close enough to reflect the camera flash in their eyes. It was raining, of course.
My son hunts elk in the stuff above, consistently killing branched antler bulls. He moved from a 30-06 to a .338 for elk, though he has a 7mm mag and a 6mm in his arsenal, and killed a 6x6 with the 6 when it was the rifle in hand one time.
A long time friend of mine in BC shoots all big game with his 220 Swift: moose, grizzly, elk, whatever. He also roped and tied up an uninjured adult caribou bull. If you've got what it takes...