I’ve had two posts in the last couple of weeks regarding ammo selection for self-defense, one on the .38 Super for self defense, and the other denigrating the 10mm. We also did an episode of Gun Nuts Radio that focused on terminal ballistic performance. Out of all of this, one of the comments that will usually show up at least 10 times is where someone touting the .357 Sig or the 10mm will point and wave and stamp their feet about how much more muzzle velocity their part cartridge has. Stop it. I have linked to this image so many times that I’ve lost count, but here it is again. Now, we’re not talking about hunting rounds here, because I’m not a hunter, so I’m going to confine this discussion solely to defensive ammo for two legged badguys.
Look at that graph. See how every single round penetrates more than 12 inches and expands to roughly 0.50-0.60 inches? The 9mm, the .40, the .357 McSilly, the .45 ACP all do exactly the same thing. They all have a permanent wound cavity that is virtually indistinguishable from one round to the next. So all that extra 100 FPS you’re getting the .357 McSilly or the 10mm isn’t actually going to make a difference in terminal ballistic performance. When you’re thinking about touting a pistol cartridge because it’s a “better stopper” because of all the muzzle velocity/kinetic energy/magic it produces, remember this from the definitive resource on handgun wounding:
Kinetic energy does not wound. Temporary cavity does not wound. The much discussed “shock” of a bullet impact is a fable and “knock down power” is a myth.
If you want to carry the .357 Sig or the 10mm or some other boutique cartridge, that’s fine. I’m certainly not going to stop you from running out and buying a Springfield XD in .45 GAP. But don’t fool yourself into thinking that your bullet is going to do something special in terms of damage to the target. If you’re using a modern, “service type” hollow point load, guess what – it’s going to penetrate 12+ inches and reliably expand regardless of whether it’s a 9mm, a .40, a .38 Special, a .357 Sig, a .45 ACP, or a 10mm.