Deaf Smith
Targets don't shoot back, targets don't move in odd directions, targets don't have innocents about them, and targets don't sometimes expose only part of themselves while shooting at you.
but do not expect to get x number of shots off nor x number of hits nor x number of GOOD hits.
Exactly. If you miss on your 1st shot or only get a peripheral hit. Can you get back on target and make the hits that you need to with a .40 or a .45? If you can. A more powerful round IS BETTER. 3 hits with a .40 or .45 definitely trumps 3 hits with a 9mm assuming similar impact points. But if you can get 2 of those 9mm hits on a moving fighting target and only 1 with a .40/.45, the 9mm is better.
However, most people who don't shoot for a living can't and therefore are less "effective" with a more powerful round that will undoubtedly do more damage on the target.
arentol
However, I would suggest that .45acp is actually easier to control than 9mm +P for many people and is a more powerful cartridge. I would also suggest it might be worth considering getting some good formal training on recoil control with .40 so you can shoot it as effectively as 9mm. Either way you benefit in both calibers and maybe you do move up to a more powerful round that might make a difference to your life or another's some day.
For some people it might be. If you have a .45 in the same frame size as the 9mm. Many .45's are larger, especially with Glocks. (The guns that I shoot the best) I have been carrying a concealed weapon since 1997 and I have been to formal training on several different occasions. The last training I did required alot of shooting on the move from lots of odd angles with less than perfect "form". The only guys I saw doing it well with more powerful rounds were the Memphis SWAT team guys, but they do it for a living. I know they were using .40 because some hot brass went down the back of my wife's pants during a drill and I had to dig it out.
I started with Glock 21, then a G30, G22, G27, G23 and finally a G19. During that same time period, I also owned trained with and tried to CCW a Sig 229, Sig 220, USP 40, Beretta 92F, Walther P5, Sig P232, S&W 409, S&W 640, S&W 686+, & Browning HP.
The G23/G19 frame size was the most concealable and effective for me to shoot. The G19 was my wifes carry gun because she couldn't control the G23. I would usually shoot her gun some too and I ALWAYS shot more accurately and faster with it than I could my personal G23. So I switched to the G19 and I went to my very 1st GSSF shoot (My 1st ever competition shoot) and got 10th place. If I hadn't gotten carried away and lost 10 points for shooting 1 extra popper on the Glock M, I would have been in 4th place.
My experience is that most people cannot control recoil without significant practice time. My advice is always to do the opposite of what I personally did.
Start with a 9mm, get "effective" with that. Try a .45 or a .40 and if you are "effective" enough to control the more powerful rounds. Go for it. I am an engineer by trade, and my life does not revolve around shooting. Ergo, I choose something that I can stay proficient with my minimal practice time.
As an aside. People should investigate what those who currently are or used to shoot people for a living and are currently in the business of training others carry and shoot.
Most of them don't use a .40 or .45....
If, however, you feel more confident with and shoot just as good with a more powerful round as you do a 9mm, I would go with that.
Personally, I don't.