RE: 223 for deer?
The only animal that is deer sized that I am intimidated with shooting is a Sika deer. They are small, but every one I have shot has been horrible tracking. I shot my first one, thru both lungs and then on a running shot, I knocked it down thru the guts, then running away I destroyed the right ham with another slug. I couldn't believe it. But I knew if he got to the swamps, I was in trouble. We made it to the swamps, and here I go, breaking out the canoe, paddling finally finding him an hour later still alive. How is that possible. The other ones wasn't quite that tough besides bow shots. Then it gets interesting. This is the toughest little critter I have seen.
An elk also is something I feel I need all the power I can get. Seen em go long and far with good shots. The moose i have killed have just acted drunk and staggered and fell down. My guide every year hunts them with a .243. I was shocked. But hes the best stalker, I have ever seen. While I use a 300RUM. Boar in WV, got to wait for your shot, but easy when you wait. Might have to let him pass sometimes. But whitetail, never worried about it.