Masaad Ayoob had a good write up about the infamous Miami shootout where several feds were killed.
He read up on the autopsy reports and concluded that the 9mms had performed about as well as they could. He said those guys were using Ruger mini 14s. He also said they fought on for a minute of two after they were basically dead.
Among wounds, I still remember that one 9mm bullet tore the entire aorta off the heart plus several other non survivable injuries. It was just that these guys were tough and didn’t drop when they were fatally shot.
Basically the 9mm performed just as it should have. Changing to a hotter caliber woud not have helped unless you are maybe talking about a .44 mag or .41 mag.
Oddly enough, it was a 38 that actually ended that fight, when it nicked the BG’s spine. The fatal wound came earlier, when a 9mm nicked an artery.
In the end, stopping power comes from hitting something vital. A bigger caliber that penetrates the same distance will increase the odds of hitting something vital, although not as much as TWO holes from a slightly smaller caliber. Two 9mm holes penetrating 14 inches will have a better chance of hitting something vital than 1 45 round penetrating 14 inches.
In the end, shooting the biggest gun you can shoot well seems to be good advice. And CARRYING a gun means carrying the biggest gun you can conceal properly - which can be a challenge in southern Arizona in summer.