The 9mm is the superior choice because it has a reputation for requiring mag dumps, so it's politically correct to burst a quick 15 rounds to center mass before the BG can even fall down. Cops routinely do this, even in groups, making it legally defensible.
Anybody who tries this with a super-dooper one shot stop state of the art caliber like 10mm or anything starting with a 4 could be charged with excessive force.
