Additional visible wound damage?
WTF is that and what does it have to do with lethality?
12ga. #7 birdshot makes an awesomely gruesome "visible wound" when compared to 12ga. #00 Buckshot, but I don't see anyone but the village idiot claiming it's a better man stopper.
It all comes down to poking a hole in human flesh, and whether you believe it or not all service caliber handguns do about the same (mediocre) job of poking said holes.
There is no magic bullet/caliber, deal with it and train accordingly.