I have the "elk rifles" in the following- 25-06AI,280 Rem,30-06, 308 Win, 300 Win Mag, 300 WSM, 300 RUM and 375 H&H.
There are many ways to hunt elk. If I was hunting private ground really all I would need is the 25-06. However, I feel more comfy with a 300 mag of some sort. Especially so given the rising grizzly population.
Most years I use my 300 RUM exclusively for everything in MT because it is like an old friend and it's been a plain lucky rifle for me.