I live and hunt in the catskills and you can't much go wrong with the old standard's,30-06,270,.308 etc..The 30-06 is arguably the most versatile with the wide range of bullet selection.If I only had one rifle it would probably be a 30-06.I would not be concerned about 400 yard shots.If you are mountain hunting 95% of your shots will be within 100 yards.