I use a 300 win mag, although I have shot elk with several other calibers. This comes down to the old question, "what is the best all around caliber?" My venerable old 30-06 has taken quite a few elk, but eventually I wanted something that was a bit flatter shooting for deer and antelope. I used to have a favorite caliber for each species, but now it is more important to have a rifle that I am comfortable with all the time. I take a 300 win mag and a 300wsm with me on all hunting trips.

I basically carry the 300wsm, but have the other for back-up. They are both similar in performance, which is critical for me if I have to change rifles for some reason during a hunt. As long as you put it in the boiler room, there is usually minimal meat damage to the ribs, etc.

The 30 calibers are also quite versitile when it comes to the availability of different bullet wieghts. I'm not knocking any other caliber though. The 7mms and 270's are still amongst the best if you have only have one rifle. My father-in-law has banged many an elk with a 270 (150 gr Barnes X's).