RE: 223 for deer?
I don't think anyone said they wouldn't work just that there are much better choices that will work better in marginal situations, heck I owned a 7 TCU which is a 223 Rem necked up to 7MM and it worked great on deer with very little recoil in a handgun. Perfect broadside shots are few and far between and head shots will work on deer also. I want something bigger if I am going to rake a shot into the vitals.