RE: .223
You can tell that guy that told you a .243 isn't adequate for deer that the last 11 whitetails that I have shot didn't agree with him. I stopped using my 7mm mag because it didn't kill any faster than my 243 and the 243 was lighter, and more accurate. I don't think you could go wrong with the .243, you could still use the lighter weight 55-60gr bullets.