Wow / A Rem.223 taken a deer down kind blows my mind! We here in the Buckeye state are limited to shotgun or muzzleloader firearms for deer. I have a Rem. 223 I use for varmit and have no dout a head shot on a long distance deer would be effective. But if I had an opportunity to rifle hunt for deer Im sure I wouldnt take my 223. Congrats to your freind on first deer and agreat shot.