I beleive the 9mm had more to do with capacity and the popularity of it with other NATO militaries, along with a flatter trajectory than the slow and heavy .45. It definitely has less recoil than the .45, but not by that much.
You must also realize that the 9mm NATO is loaded to a higher pressure than typical 9x19. I think it's equivalent to something between a +p and +p+ round. If you've ever fired a really hot 9mm or +p+ round, it doesn't feel very less powerful than a .45. The type of weapon you fire each from plays a part, of course.
edit on 11-6-2011 by deesul69 because: (no reason given)
