It looks like the .223 is NOT high caliber, but it IS high velocity.
The high velocity gun shot wounds have variable rates of survival, primarily predicated upon the site of trauma. Obviously, if a major artery or vessel is severed, you're dead. On the other hand, I recall seeing multiple patients as a lowly medical student and watching the heroic trauma surgeons saving life. I remember one patient where the intern was showing me how to clean bullet wounds and attempt to identify the location of the round in the body. The patient was talking to us and we stuck a long cotton tipped swab into his neck wound... As this 4 inch long swab went in one end, the intern realized...it kept on going through his neck... right through the other side! It was cool... the patient lived too (too bad he was just another inner city gang banger type).