If you're concerned with over-penetration on a person, I don't see an issue at all if you are using HP ammo. If you're concerned with over-penetration of a wall in your house if you miss, any ammo that is designed to poke holes in humans will blow through drywall like it's not even there, irregardless of the caliber. That's why practice is essential.

Along that line of thought, one of my research resources was a Fayetteville cop. We were talking and he had mentioned the fact that most confrontations would involve not that much distance between himself and his assailant. He's currently carrying a glock 45, but would rather use a shotgun for defense once he's certified. The main reason being where the round ends up if he misses his target. I hadn't even thought that far ahead.

Two suggestions: Suggest you use a good quality SD HP (eg Ranger T, Gold Dot, HST). Also suggest you not pay too much attention to advice from your shooting buddy.

A good quality 9mm HP is no more susceptible to over penetration than any other SD pistol round.

Never heard anyone call the 9mm a "small diameter" bullet. Or" high velocity" for that matter. The 9mm is about the same diameter as the 357 Magnum, and never heard anyone call the 357 Mag "small diameter" either. While the standard SD bullet weight for the 9mm is about the same as the 357 (124gr vs 125gr), the velocities are quite different. A 357 is a high velocity pistol round, a 9mm is not.

Thanks all for the replies. I was thinking along the same lines as the rest of you. Just wanted a second opinion.
Now I just have to decide between 9mm and .45. Any opinions on this considering the same pistol chambered for either caliber? Meaning XD9 vs. XD45, FNP9 vs. FNP45, P250 9mm vs. .45. Concerned with mussle flip/ follow-up shots. I've shot my son's XD40 and it's kind of hard to do quick follow-up shots(double taps) with it due to the mussle flip. I assume this a characteristic of the .40 S&W round, not realy a gun related occurance.
Thanks again

Actually, it is partially gun-related. A heavier gun has less flip, and a lighter gun has more. Muzzle flip is part of shooting, and can be dealt with.

Neither caliber has anything wrong (and BTW - your information source is a parrot - don't you be a parrot too). Both will do the job if you put it where it needs to be, and neither will do the job if you don't.

Although I have three .45's, none are used for defense purposes. My home defense handguns are all 9mm, and my personal carry handguns are mostly 9mm. 9mm has the advantage of larger capacity, low recoil (subjective, of course), cheaper to shoot which allows more shooting, and easier to find locally if I need to.

If you are like most people and thing that more equals better, then get a larger bullet if it makes you feel better.


btw - what's a "mussle"? Is that like a mussel, or a muscle, or perhaps a muzzle?......

HAHAHA
PhilR., you're right. That would be muzzle not mussle. I was in the process of trying not to burn dinner at the time
O.k. So 9mm or .45ACP won't be a problem with overpenetration if put on target. Any insight on the differences in shooting the different calibers of the same gun ?