It's a little more than just elevation. It's, as you put it, enough energy on impact. With the .308 you can have heavier bullets to make up for the loss in speed with the energy stored in the mass. Greater weight=more downrange momentum and penetration. But the question still remains, what animal are you intending to hunt and at what ranges will you limit yourself to. If just whitetail/mule deer then a .270 is just dandy out to 400-500 as far as energy is concerned. But if you are talking Elk or Moose then you will want to up the ante for those ranges and use the heavier line of bullets from the .308. Sounds more like to me you are wanting a more effective mountain rifle that you wont be taking overly long range shots with. My personal preference would be neither in your situation. 7mm-08 in a nice handy mountain rifle configuration is about as good as one can get for whitetail/mule deer or if you are stepping up to Elk/Moose then a .338fed in the same configuration. I hunt Elk with my 7mm.08 often and have found it highly effective out to ranges of 250 yards or below. I've also hunted Elk/Moose with my .338fed barrel on my TC and it is a dream of a cartridge as well. I personally have never been one of the .270 fan people because honestly I can load up a .30-06 round to beat it every single time. Not a huge fan of the .308 either as there are just too many rounds based off that cartridge that are better both ballistically as well as energy down range.
Last edited by super_hunt54; 12-02-2015 at 09:35 PM.