Featherweight 30-06=near ideal mountain rifle.
You could load a 165 grain bullet to 2900+ fps. Mine registered 2912 average for five, over an Oehler chronograph, with 31 fps spread and absolutely no excessive pressure.
The difference in trajectory between this and a 130 in a 270, would likely never be seen in the field.
But, don't make the mistake of weighting that nice rifle down with a large, high power, variable scope.
If you are a trained shooter with high quality aperature rear sights and good post for a front sight, I could put up a good argument for using this in the mountains. I have shot quite a few mountain game animals with just such a rig, and never failed to kill every one I shot at. The rifle is just such a dream to carry, as compared to one with alarge scope. I have never cursed my aperature sights in the mountains, but I have sure as hell cursed a new "fogproof" scope, that got so fogged up I couldn't see through it!
Back in the days when shooting and hunting were words you proudly spoke in any company and scopes were coming in to their own, it was always the lower power ones used. Many a well heeled hunter, hiring a mountain outfitter with a huge string of horses for a month long hunt in the Rockies, would have a fixed power Weaver, usually a K4, on his rifle.
In my opinion, the best scope for your light mountain rifle, would be a high quality, fixed four power.