30 plus caliber is designed to kill with one shot, below 30 caliber requires two or more rounds. If you want to kill your attackers, use something like a .308, if you only want to discourage them, use a .223.
The .223 made some sense where guys are truckin it thru the bush, I guess. That way they could carry a lot more ammo to piss people off.
I like the idea of putting someone down and out with one shot.
Dead enemies are just dead. Wounded enemies are a burden on their comrades and make much better intelligence sources when captured.