There is a lot of good information in this thread! As an Ammo Troop in the USAF, I get a h@rd-on for these types of topics.
After reading up on this for most of the morning, I found that all weapon systems are doing their respective “jobs”.
.45 is effectively killing/destroying things.
5.7mm is effectively putting little holes in paper, relatively accurately.
And 6mm airsoft is effectively keeping the neighbor’s dog from pooping in my yard. Well sort of, but I blame the intelligence of the animal for the repeated “shootings”.
No opinion on the .40 topic…
FWIW it is generally a good idea to consider the input of the subjects in the field as opposed to the input provided by the “experts” in the rear. If I were Barney, not only would I listen to the QP’s, I would also put the ultra-high capacity of both the p90/ps90 and the Five-Seven into the equation.
I find a .45 caliber hole staring at me a lot more intimidating than a 5.7mm hole. Sun-tzu said “attack few with many”, so I give me most caliber I can handle.