Congrats!
Nothing like scoring your first! How'd the .223 do in terms of "stopping power" by way of how far did he run after the shot? A lot of people knock the .223, but a well placed shot should be pretty effective.
He ran about ten yards down a ridge and then fell over into the top of the valley. I guess it stopped him pretty good, but I'll never shoot with .223 again if I can help it. There was no impact blood or hair and if I hadn't heard him fall over that ridge, I'm not sure I would have found a trail. The only blood I saw was where it pooled under him.