Yeah, I'm not saying a .223 won't kill a deer. It obviously will. Personally I've NO experience with that caliber. There is always a difference between what can do the job, and what the average hunter would be wise to use. I know people who kill elk with a .243. Personally, I prefer a bit bigger caliber, not because the .243 won't do the job, but I prefer something that will increase the odds of finnishing the animal off more quickly if I fail in my accuracy. Wyoming doesn't allow the hunting of big game with any thing smaller than .23 caliber. They have to draw a line somewhere in compensation for a lack of judgement on the part of some hunters. No doubt there are many wounded and lost animals around the nation that were shot with the larger magnums as well. The .50 caliber would probably be the best choice to put the animal down....but do we all really want that! lol