Bear,
The folks here at huntingnet.com must have hired you to drum up traffic since it seemed to be slowing down with the fall hunting season fading in the distance. See these q' s everywhere....... is kind of fun responding to them though.
(1) Got to be careful applying generalities to specifics, so a few questions:
What guns do you already have? Rifle cartridge " spacing" within your rack is important, no sense it collecting a bunch more " mid-ranges" when you already have some!
(2) Are you tough or tender when it comes to recoil? Don' t want anyone running home to mama to get their shoulder bandaged.
(3) What are your hunting plans (species wise) beyond elk? Got to look forward to the future.
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With that said, for NA:
Little cartridges and Little guns for Little animals. (varmits/coyotes)
Medium cartridges and Medium guns for Medium animals (antelope/deer)
Bigger cartridges and Bigger guns for Bigger animals (elk, moose, great bears)
Elk aren' t Little and they aren' t Medium. They are large and by that I don' t mean they are like " large, large, large deer" they are not. Deer are fly weights by comparison and are only half as tough as elk.
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If you don' t have a high power rifle (30-30' s don' t count
) then go for a 7mmMag or 3006 if you' re tender or 7mmUltra Mag or 300Ultra Mag (your list) if you' re tough.
If you do have such a rifle (in the 7mm to 3006 range) and feel you just HAVE to go out and buy something then " space out" the new rifle you will be adding to your rack AWAY from what you already have and move up to something like: 338 WinMag or a 8mmMag (your list) if you' re tough and something like a 338-' 06 or 35 Whelen if you are tender.
What ever you do don' t get a 375 like Ranger Mac or myself -- even though they are world class hunting rifles -- it causes entirely too much hand wringing, consternation, and loss of sleep among the troops here in NA.
Never Go Undergunned
EKM