But sometimes you don’t. It takes a certain amount of ballistic energy to create both expansion and penetration. If you do ever get a chance to test bullets in gelatin, you can see that. Sometimes more speed can actually decrease penetration, due to bullet over-expansion and the drag it creates.
If the caliber you have and the load you are using (or are stuck with) can’t generate enough oomph to do both, you have to pick one.
Now, the FBI calls for between 12 and 18 inches of penetration. When you consider that most people, from sternum to spine, are 9 inches or less deep, 12 should be plenty. So what do you do with an expanding bullet that delivers only 6, 7 or 8 inches of penetration? Why, you opt out of the expansion part of the equation, that’s what.
The likely candidates here would be a snubbie .38 Spl., a .380 Auto and a .32 ACP pistol. Yes, yes, I know, they aren’t “manly” calibers, and no serious operator would be caught having to admit they owned one, let alone carried one.
Except, we’re not all operators.
Your grandmother, who refuses to leave the old homestead, where she’s lived since Dwight D. Eisenhower was running for office? Can she handle a 9mm +P load? A .40 S&W? No, she probably can’t. But the 4-inch parkerized Victory Model S&W that her older brother brought back from The Pacific? That she can handle. Just don’t load it with +P .38 Spl. ammo. It will handle +P better than she will, but she won’t thank you for that ammunition.
All the top-performing loads for it will be +P, so you use standard-pressure ammunition. And since the likelihood of any of them expanding at those velocities is pretty small, use what is soft to shoot.
In the .380 and .32, you need jacketed ammo. FMJ expand? Not a chance. You aren’t going to get one of those to expand unless you use a ball peen hammer and an anvil.
But what you can count on with all of these is sufficient penetration.
That’s why the Los Angeles Police Department has issued guidelines for its officers. Those who are carrying a .380 off duty are advised to load it with FMJ ammunition, in order to ensure sufficient penetration.
What FMJ ammunition for you, then?
Simple, the same metrics we use for any ammunition: it has to be available, it has to be reliable, and it has to be accurate.
In the case of these three calibers, the choices are wide, and you will have no problems finding something suitable.
However, in the case of your grandmother, or someone else who might be lacking in hand strength, you might have to do the bulk of the testing yourself. So, here’s a tip: pretend you are 80 years old.
That’s right. Check the reliability of the ammunition, in the selected firearm, by deliberately “limp-wristing” it. We’re all told to get a firm grip, but what is firm for your friend, grandmother, whomever, might actually be pretty weak. So, do your best to make the selected EDC/Home defense gun malfunction in testing. Even go so far as to hold it with just thumb and second finger, letting the other two fingers hang out in the breeze. Hold it as loosely as you can, short of dropping it, to ensure that it will function when someone much frailer needs it.
And for revolvers, consider just how much finger strength your student has, and if they will actually be able to fire it double action. Because if they can’t, they will thumb-cock it, not be able to lower the hammer later, and on your next visit you’ll find it someplace in the old homestead, cocked.