Do yourself a favor and try to read this article without laughing. http://wildernessmastery.com/hunting/223-for-deer-hunting-ammunition.html A few quotes: "The aerodynamic of a shot is determined by the increasing level of the ballistic coefficient. Normally, higher calibers are considered to have the best ballistic coefficient. However, the .223 has just the perfect coefficient for hunting deer." "Unlike most big game ammo, the 223 is not heavier in the air and they are not often unstable. The best stability is based on the weight. The next thing to consider is the bore surface, which refers to the length of the shell that dashes the bore." "A 308 caliber will develop a needle-like wound; the same cannot be said of a 223." "If you are shooting at 300 yards, your main challenge will be to maintain the transonic speed."