I have a similar rifle - walnut stocked mountain rifle in .280 Remington. It seems to favor 140 grain bullets - the Ballistic Silvertips from Winchester shoot very well, unfortunately I've not had good luck with them on game- they seem pretty frangible even on deer, although that may because my experience with them is at close range - of the roughly half dozen deer I've harvested with the combination the longest shot has been about 30 yards. They don't seem to penetrate the chest cavity even at that short range. Although all the deer died so I guess maybe the bullets did work smile ?