IMHO the .223 is not a deer rifle, at least not for U.P. deer, perhaps Florida deer, especially in the hands of a youth. But, I'm a big bore freak. I suppose, because of that, we don't allow anyone to hunt deer on our property with .22/5mm rifles. If they have nothing larger, we'll loan a rifle. I have a real aversion to roaming the woods at midnight with a flashlight looking for wounded deer, and I've had to do it.
Now everyone will post how many deer they've killed with .22s.