Nobody wins caliber wars but I'll bite
I don't
hate the 40 S&W but I never warmed up to it. It terms of diameter, the 40 S&W falls exactly between the 9mm and the 45 ACP. I never felt like the gap between 9mm and 45 ACP was a big enough gap that we needed to put something in the middle, but we did just that. I'm not saying it was a bad idea to fill that gap, just saying I'm not sure we
needed to fill that gap.
I also would not say that the 9mm is "....just as
powerful and effective as the 40 S&W" but I will say it is just as
effective.
I find it interesting that a 9mm bullet of .355" diameter, weighing around 115-125 grain and easily travelling over 1200 fps is often considered by some to be inadequate and yet that's far more energy than most 38 Special cartridges deliver. The 38 Special was, and still is, considered to be an adequate self defense cartridge.
When you get right down to the truth, all handguns are rather poor tools to stop a human attacker. Some handgun rounds are better than others but NONE of them are great at stopping human attackers. A handgun is better than harsh language but not as good as a long gun.
When one looks at actual results from shootings, a 115-125 grain +P 9mm hollow point has a pretty good track record, as handgun cartridges go. The 40 S&W is no slouch but nor are other common self defense cartridges. None of the common handgun cartridges significantly stand out above the pack. A 38 Special, 357 Magnum, 9mm Luger, 40 S&W and 45 ACP are ALL capable of penetrating deep enough to stop a fight.
A lot of people are fond of pointing out that a 40 S&W cartridge delivers a bullet that is
heavier than a 9mm projectile and
faster than a 45 ACP projectile
BUT.....
I like to point out that the 40 S&W projectile is
lighter than a 45 ACP bullet and
slower than a 9mm projectile.
Like I said, nobody wins caliber wars.