“Mountain hunting” for me has always involved out of state travel, which in itself means increased expense, lesser familiarity with terrain, and shorter duration for opportunity than hunting in state. It also means I’ll be a few thousand feet, or SEVERAL thousand feet above my home elevation. I have hunted deer in over 20 states in my life, so in recent years, about the last 7 years, out of state hunting also implies my primary target is a NON-deer species. My preferred method of mountain hunting is on foot, again, reducing cost and complexity (my horses also only live at 1300ft), and I prefer to travel deep backcountry where I can get away from other trappings, and other hunters.
For me, that boils down to defining “mountain rifle” as a relatively lighter rifle than I might otherwise use at home, but also chambered in a more powerful cartridge than I might use at home, capable of allowing me to place a 600-750yrd shot with increased confidence in blood letting and fast anchoring.
Far from what I consider to be ideal, my current mountain rifle for about 6yrs has been a Ruger M77 Hawkeye All-Weather in 300 Win Mag, which I restocked into a stiffer Boyd’s laminate stock. All in, as hunted, it’s over 11lbs.
If I had my druthers and spent the money for an ideal rifle, as mentioned in the other mountain rifle thread, I’d build a Seekins Havak Element (aluminum receiver) with a carbon fiber wrapped Bartlein barrel, using the extra length Seekins short action carbon fiber magazine system in a mid weight McMillan Game Warden stock, chambered in 6.5 PRC. I’d be content with this, replacing the 7mm Rem Mags I’ve also used up-mountain many trips, capable of deer, elk, or bear out to 750yrds.