There is really no margin for error in a slightly misplaced shot that a bigger/faster/wonder bullet may make up for.
The 223 kills deer graveyard dead IF you can hit them exactly where you are aiming too. Which is easier with a 223 because there is no recoil to worry about and the round and rifles for it are usually tack driving accurate.
The 223 is no cartridge for the general population to go blim blaming at every deer they see and hope for the best IMO.
But if you are a cool customer, willing to pass some shots offered and confident enough in yourself and your gear to KNOW you can hit the spot you are aiming at then the little 223 and plain old cc bullets will work like a charm. Notice I did not say just hit the deer, I said hit the spot on the deer.