Elk, like deer, are getting tougher and tougher as the earth warms, so your gonna need a minimum of a .375 H&H...

My go-to elk rifle is my Sako chambered in 340-Weatherby.

338 Win Mag is first choice but my 270 Win would do. Now that I have Granpa's gun back in the family I might have to use it if for nothing else the sentmental value, 375 H&H Mag w/ 270 gr bullets.

I use a 338 WM with 250 grain bullets and have never had a problem with elk or moose. Out of the 3 you mentioned, I'd say 30-06. Most hunters will tell you something 30 caliber although there are quite a few that use deer caliber guns with heavy bullets and do just fine. In the end, it depends on what you can afford, what you like and what type of hunting you're going to be doing.

As a former guide and longtime resident/hunter of the Rocky Mountains, I think way too much is made of which caliber is the best elk cartridge.
My first gun of choice is the one I have the most faith in. The one I am the most cionfident in. That is what is supremely important. Sure, a large magnum will knock 'em down at farther distances, but how good a hunter are you to not be able to get "within ethical range". And how much flinch can you subdue when it comes down to the rubber hitting the road? Besides, I tend to think that the large guns tend to give a hunter false hope.
So use the rifle you are most comfortable with and don't fall prey to "how big is your gun?" Capice?
Naturally, you don't want to go after a rhino with a fly swatter either. The biggest gun you can trust and comfortably shoot, that's the gun you take. Also, Launch a bullet that penetrates bone and flesh well and then opens up to do damage.

Then you practice, practice, practice!!!!

Thanks guys!

There is no better answer to your question. Stop at this post.

Tom

A .270 will put him on the ground, but you might want that .338 to insure you can get out of grizz country with your game.

plain simple savage 30-06 with redfield scope.not fancy or expensive but i like it

ya know maybe a 416 rigby,dont wanna be undergunned