The reality is that a pistol was never a real stopper regardless of era. As I recall one lawman got shot 18 times and never killed.
No, the 45 has no significant upside over 9mm these days for Police. Military is an odd area I am not going to try to go into other that a JRN of 45 cal is no more effective than the same in 9mm as they both just poke holes.
The change is the vast improvement in SD ammo. Lead slugs at one time would have incurred a better odd as they (if done right) would expand. As thee 45 ACP cold not be made in lead (granted truncated cone type and good feed ramps change that)
Upshot is that SD JHP works better, 45 improve some, but 9mm benefits even more. All the data says they are so clse to equal as to make no difference, its all statistics. One day a 9mm was very effective, the next its 40, following day 45 and some days none of them do what you need.
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Take into account the fact that a wounded person takes more people out of the battle than killing a person and that the pistol is not the primary weapon...no need for the extra weight.
I have heard that repeated endless.
In this case for a pistol fight in the military its not remotely applicable. If it gets that close the last thing you want is to wound someone who can still kill you. There is a high chance it will happen with pistols, but that is a by product not an intent.
For a main battle, you want to kill people. Wounding them unless severely means you still have a soldier (or whatever) that can still shoot and kill you.
Its a phase that has slipped into the lexicon that has no merit. Longer term is equal to both side sans a ISIS type.
ISIS or Taliban?: They die or they go home and get patched up. Taliban particularity ally tend to be seriously toughly raised people, they don't die easily and the 5.56 just pokes holes in tgheir skinny bodies.
Reality is that it takes a very Targeted round be it rifle or pistol to outright kill someone.
Some do it in a little longer, some longer yet and some not at all.
9mm has a benefit of more rounds and easier to control and so close to equally effective that its simply the person who is accurate enough to make a hit that wins.