I have a Browning A-bolt 7 mm wsm and I used it elk hunting last fall in SW Montana. I could not convince an elk to partake in the target practice, but everything I have heard is that the smallest you would want to go elk hunting with is a 270. A lot of folks swear by the 300 win mag. I happen to think as long as you know the ballistics of your weapon like the back of your hand and can accurately place that bullet out to 300-400 yards then you should be fine with whatever you want to shoot with. I got a 7 mm wsm because it is a very flat and fast gun that I can use for deer hunting and elk hunting.
I am a member of Sage Creek forums and they have a General Firearms section and there has been 100's of threads talking about the different caliber sizes for elk.
http://www.sagecreekforums.com/phpforum/viewforum.php?f=63
I feel there are much more important things to be worried about than your gun.
[ol][*]Being accurate with your weapon.
[*]WIND.
[*]Optics.
[*]Being in shape for the hunt, mentally and physically.
[*]Understanding elk behavior.
[*]There are many more than I have listed here but this is just the tip of the iceberg.[/ol]
Dewey
�Strength does not come from physical capacity. It comes from an indomitable will.�
Mahatma Gandhi