Personally, I agree with the .308WIN chambering.
I have reloaded .308 from 110 grain to 220 grain bullets, most of which was just to squeeze a little bit more constancy at a speed and trajectory I wanted over factory, but most of those were available in factory ammo. Mountain hunting I have used 125gr and 150gr bullets with great success in mid to lighter weight rifles (6.5lb rifle plus scope, rings, sling and ammo).
Also, .308 ammo is easier to find in case you get all that way to your hunting area and find out you forgot ammo (rare, but I have heard it happening).
Plus, .308WIN is chambered in so many different rifles from cheap and expensive rifles, ultralight to heavy target rifles, wood or composite stocks, and likely every type of action (break, bolt, semi, etc) made. It is easier to find that rifle comfortable to pack, carry and have confidence in shooting if you have so much selection.
Someone will say that the .260 Remington is the ultimate cartridge for mountain hunting and out preforms 6mm & 6.5mm Creedmoor every day of every year (and they might be right) but also they might be reloading it for a long time, have a very expensive gun they swapped the stock on, and have spent more time and money than we both can afford combined.
My opinion, and someone will object I am sure: just keep it simple and don't over think it.