What I mean is that 9mm feels like it snaps more in my hand, but doesn't put as much force into it. For me it is the combination of the faster round and the sound of it, with the faster 'pop' from the barrel. It doesn't cause as much muzzle flip or as much pressure backward as the .45 for me. But the pressure it DOES create is a quicker 'pop' or 'snap'.
For me the 9mm has less rearward thrust than the .40 or .45, which is why I can recover faster and get more rounds on target in less time. But, the supersonic round [anything over 1130 fps] and the faster recoil impulse makes if feel like a 'snap' to me, rather than the slower and more forceful 'shove' or 'push' of the .45acp round.
So what I meant was that the .40 shoves back as hard as the .45 in my hands [reducing recovery time compared to 9mm], while 'snapping' or 'popping' more in my hand [due to the faster round causing a faster recoil impulse/cycle].
So I can recover target acquisition fastest with the 9mm, I can ride the .45 thrust back to target acquisition easily with the .45 [as it is a relatively gentle strong thrust], but the .40 feels like a more violent rearward thrust that is the hardest for me to overcome.
Trying to use the .40 alone for the first year, and actually firing it only about once every 3 months, allowed me to develop a serious flinch that took me years to overcome. Of course, when I started to overcome it is when I started to hit the range every 2 weeks or less, and I worked with a .22lr for 2-300 rounds per range session to work the flinch out. And THEN I started the ball and dummy drill and others to work it out with 9mm and .45, before finally, 10 years later, picking up another .40s&w.
I've fired a 10mm for one magazine worth. It was a Glock [21? 20?], which meant it didn't fit my hand right. For me, the 10mm was something like shooting a cross between a overpowered .357mag and a moderate powered .44mag, but in a platform that felt 'wrong' in my hands. Sorry people: I'm one of those who don't care for the feel of a Glock in my hand. I have one, but only one.
I intellectually like the idea of a 10 round handgun firing rounds that are at least as powerful as full-powered .357mag, and closer to entry.44mag numbers, but with 4+ more rounds in it. If I lived outside of California [or New York, or a few others], I'd also like the idea of having 12+ rounds of that ammo to fire at once.
However, I'd have to try it in a different platform. A 1911 platform would feel better in my hands, but then I'm talking adding a $1000+ gun for 2-3 more rounds of the same power as the GP100 or SRH I already have and enjoy. Plus the ammo for the .357mag is both cheaper and easier to find in my neck of the woods.
I have too many toys [my wife's words] for that experiment. I'd be more interested in a 10mm top end that would work on my M&P .45 frame [if the frame can handle the 10mm full power stuff].
But, recoil wise, it was a .40S&W on steroids, putting it above .357sig and closer to top powered .357mag rounds. I like .357mag and .44mag. I can shoot a box or two of the stuff without trouble [unlike my dad, who does 2 cylinders of .44mag and is done]. The 10mm is manageable, but is in another class above the recoil of 9mm/.40S&W/.45acp.
And yes, I know the arguments that 10mm is what .40S&W SHOULD have been, before it was downloaded for the FBI, etc.