RockyMTNG20,
There is absolutely no reason to go any higher than .308 cal for elk. The last time I saw a Roosevelt Elk, and that was about a week ago, they had not been issued armor yet! These boys are a touch bigger than the Rocky Mtn Elk, and they haven't been issued any armor either, from what I have heard!
Where are you going to be hunting your elk? Are you familiar with the terrain? What about the tree situation where you will be hunting? Is it thick trees and brush or open fields? Will 300-400 yard shots be the norm, or will 25 to 200 yards be the norm? All Of these questions will give us more info to help you decide better on what caliber and type of rifle you should really be getting. Oh, are you recoil sensitive? Have you been shooting a long time or are you fairly new to the sport.
Those are some of the questions you need to answer before deciding on the caliber and style weapon you are going to use for your hunting. If you don't know, or just can't answer these questions, get a 30-06 and call it a day! Ammo is in every mom-n-pop store in the country and it will take any elk that gets in front of you out to 300 yds with good shot placement. I convinced myself that I
needed a 300 Win Mag. I wish I would have gotten a 30-06 instead. Seriously!
I should not get a light weight rifle for .30 and above, it should be at least 12lbs above for .30 & > and finally, that a mountain gun should weigh no less than 7 lbs before scoping it.
How's that supposed to work. Oh yeah... a 30-06 or even a 308 would do just fine in a lighter platform. You do not want a magnum that weighs less than about 9 or 10lbs with a scope on it, but a 308 or 30-06 will do fine. Heck, even a .270 would take any non-dangerous game in North America!
Mike!