“n fairness, they describe centerfire rifle cartridges as “large caliber” regardless of their diameter because of the energies involved, just as they classify .38 special as “medium” and .357 magnum as “large”, despite them shooting identical bullets.”
But they don’t even show the .223, just the AK-47 round. And the best advice is carry the gun you’re comfortable with. My wife has a .32 Autp Beretta Tomcat because she has arthritis and has difficulty with the slides on her larger handguns now. It may be “small caliber,” but with good shot placement it’s an effective weapon.
There were no shootings from a .223 in their data, so they didn't include it.