I have killed them with 270 WBY, 25-06(IMO the perfect goat gun), 45 Inline.

Have seen them killed with 243, 308, 30-06, 30-378WBY, 35 whelen, 50 cal inline, 280, 7x57, hmmmm.....all your guns will work. I would take the one you have the most confidence in. MOst are killed closer that you'd think! 150-200 yards seems to be the norm.