Quote Originally Posted by Compost View Post
So for military purposes there are two reasons why 9mm medium power pistol ammunition is better than 10mm high power ammunition that also weighs more. One, a lightly built male (or female) can better control a 9mm pistol because it has less recoil energy than the 10mm pistol. That heavier recoil is less of a problem with a 10mm SMG but still somewhat applicable. Two, for a given system weight the lighter 9mm pistol and also SMG can deliver more of those almost inevitable or irrepressible follow-on shots. And more initial shots also.
That rationale is one reason for the continued success of the 9x19. I personally think bullet strike effectiveness trumps the recoil issue which can be remediated by better training (and firing more rounds in that training, which is expensive... ) and that the weight issue is valid but given the number of rounds generally carried, not a major issue.

No matter, the 9mm is here for better or worse and while I personally prefer the .45 ACP for both pistol and SMG -- and I have used both calibers in combat and training in both weapons -- I do happen to be a big guy and I'm quite sure if I were a 5'3" / 160cm female, I'd disagree with my self.

I think I'll go find some more windmills...