Yup.
Placement.
But.
How come nobody talks about straight line penetration in terminal performance anymore?
A .22 short to the brain stem and most people can guess correctly at the end results.
But what happens if, with a light projectile, even given placement is perfect, it deflects in terminal performance and misses its mark?
Seems to me, the current trend in lighter/faster/more ignores sectional density, which if I'm not mistaken, is what .45acp has going for it next to its diameter.
In the current "state of the debate" it seems like physics doesn't matter. All else being equal (energy, placement, etc) the caliber with the greater mass will have greater sectional density and will be more prone to reward good shooting (placement,again) with a better chance that the projectile will give straight line penetration in terminal performance then a lighter projectile.
Am I wrong here?
Anyhow, to answer the OP to the best of my ability I think that 10mm, .40, and .45 would be fine with FMJ solids (yes, a flat meplat gives an edge over round nosed ball) as they all have heavier weight projectiles with the 10mm having the edge because it delivers more energy then the others to boot.
9mm ball OTOH is not in the same league. Its just not. While I don't doubt its lethality, I do doubt its ability to stop. All the stories told about WW1 and WW2 encounters with both handgun calibers and the results don't convince you, I sure can't. And I'm not gonna try. To each their own.
PS-
Don't know any other way of saying this, but I place absolutely no credence in the FBI right now. None. This includes anything they have to say about the caliber they think is best to issue to their employees, which is the genesis of the current 9mm resurgence (coupled with smaller guns chambered for it and modern JHP's which work just as well in .45 too). I like 9mm just fine (wearing one right now) because it runs well in the current crop of small, easily concealable guns and offers a good power/recoil balance in them. But it ain't .45 or 10mm, it ain't even a .40, and you know what, this might ruffle some feathers- but when comparing short barrel guns I hold that a 158gr LSWCHP from a 2" snub has a little bit of an advantage over the bantam weight 9mm para.
9mm works- but bigger IS better.
Of course, this is just my opinion, YMMV.
I tend to be somewhat contrary and run against the herd anyway........