If you are in the military and your only choices were 9mm hardball or .45 hardball, .45 wins hands down. And who cares if a double-stack-mag .45 is bulky if you’re a soldier, and you don’t have to conceal it?
But for civilians who can access modern defensive ammo, 9mm is plenty of terminal effects in a small package.
Compare a 9mm cartridge to a .38/.357. Size for size, the 9mm packs a punch.
I carry the Bersa 9mm UC Pro with two extra mags which I converted from Beretta to Bersa use. In the gun are hollow points 115gr +p and the extra mags have ball ammo in 147 gr +p. Night sights. Round in the chamber is a 147 gr ball round, to ‘get the attention of the target’.
I’ve owned ‘em and liked ‘em and have studied the ballistics.
Still it is good to get the practical word from a trustworthy source.
Cheers!