Can't go wrong with a 308 or 30-06.

What if you are offered a shot at a 250lbbuck at about 100 yards. He's quartering towards you so you need to get through the shoulder to hit the vitals. Will a 50gr bullet from a 223 have enough power at 100 yards to penetrate the heavy muscle and plow through the shoulder bone of a 250lb buck? will it getthrough that, wreck thevitals and exit in the back far quadrant of said buck? Sure, 50 yard shots at broadside standing deer is easy. A tough angle at the buck of your dreams? Why chance it with barely enough gun? Why not be prepared for anything?