I have seen more deer shot with the .223 than with any other cartridge. Some people consider it a neck shot only deal, but I'm not in that camp. If you use an adequate bullet, it will perform just fine using it as you would any other caliber.
Within 100 yards, it will make short work of any deer found in Texas (probably any other place as well.) I would limit myself to 300 yard shots with an accurate rifle, but that is pretty much the outside of my abilities with any other rifle either.
I know many people think it is inferior for medium-sized game, but I have seen it work too many times to buy that. I have never personally used it, because I'm not set up to. But if I had one with an adequate twist for heavier bullets, I'd use it in a heartbeat.