What caliber did he use?
Not 9mm, not .40, not even .45 ACP.
(Pretty much the ballistics of a .357 magnum in an auto style cartridge).
(ok, not exactly, but close…..forget the minutiae here and concentrate)
Mass matters, but velocity matters as well.
The .357 Sig delivers a pretty good combination of both.
Is there a perfect cartridge for defense? Probably not. But the .357 is probably one of the cartridges on the “ideal” category.
Would a 9mm have done the job? Maybe. .40? Likely. .45? Most probably.
Placement matters as well, and by all accounts, his aim was good and his placement was spot on.
What you carry is your choice. I want a cartridge/bullet/firearm combination that helps me to get the job done should I ever need to. (and I hope and pray that I am never in the position he found himself….but that I can do as well if I am).