A popular phrase among defensive shooters is "Friends Don't Let Friends Carry Mouse Guns." But, just what exactly are Mouse Guns? In my view, that is any defensive handgun with a caliber smaller and less powerful than the .38 Spl. and 9 mm pistol cartridges. Now, before you get all of your nether garments in a wad, let me explain my reasoning.
I frequently hear people point out that there are more deaths caused by the .22 LR than any other cartridge. While that may be true—I really wouldn't know—there are two problems with that premise where defensive shooters are concerned. The first is that death may well occur from a .22 LR wound but it may take hours—sometimes days—to accomplish. You are talking about hours and days when it is seconds that count in a gunfight. And, while I have singled out the .22 LR, the same can be said for the .25 ACP, .32 ACP and .380 ACP.
But the most important condemnation of these mouse gun calibers is, causing death should not be our goal. Our goal should be to stop the violent criminal attack as quickly as possible. If death results from the crook's poor choice of victims, so be it. But this is not and should not be our goal. We must stop the violent action before good people get hurt. It's as simple as that.
The best way to accomplish this goal is to use a defensive caliber that can reliably penetrate into the vital area. It must deliver enough shock and tissue damage that the criminal loses all interest in pursuing his unlawful actions. The .38 Spl. and 9 mm represent the lowest part of that dependable power level.
Calibers smaller than the .38 Spl./9 mm platform may be applicable for those who have some sort of infirmity that prevents them from using anything more powerful. And some might argue, "Yeah, but my little wife..." Well, be careful with that because I know several 100-pound women who can clean your clock with a .45 ACP and one of them hunts with a .454 Casull, too.
Fortunately, the firearms manufacturers have seen to it that no one really needs to carry a mouse gun for complete comfort and concealability. There are quite a number of small revolvers and compact 9 mm pistols from which to choose if "small" is your criteria.
Defense guns are like raincoats. You don't need one very often but, when you do, a small one isn't going to do much good.