Is 10mm Too Much for Home Defense?

This is a guest post by Andrew Betts

Is 10mm “Too Much”?

There seem to be two camps when it comes to the utility of 10mm. There are those who believe it to be God’s second great gift to mankind, the first being the 1911, which was bestowed through His prophet, John Browning, peace be upon him. Then there are those who believe it is “too much.” Too much penetration, too much recoil, too much money, you name it.

Now, I’m not the kind of man who’s particularly interested in telling another man what to do. You do what suits you best. Heck, some people juggle geese. But if you’re one of those in the second category, I’d like to dispel a few myths for you. If you still disagree, that’s your prerogative, but at least you’ll have learned something.

Background

Most of us know the story of the 10mm so here’s the Cliff’s Notes version. No, it wasn’t handed down to the prophet Cooper on Mount Sinai. Yes, it involved Col. Jeff Cooper, Norma, the FBI, and Smith & Wesson. No, the FBI didn’t ditch it because the stout recoil was too much for their pansy agents. It just turns out that with stouter loads, 10mm does recoil more than 9mm or .45 ACP and that heavier recoil slows shooting.

Defensive shooting is a balance of speed and accuracy and 10mm simply caused people to shoot more slowly than they could with other service calibers, no matter how manly they were. It was also apparent that it could be loaded to lighter levels (the “FBI lite” load), still be effective, and users could shoot more quickly. At those lower power levels though, the extra case capacity wasn’t needed.

Of course, that’s how the .40 S&W was born. But you already knew all that.

“Overpenetration”

First off, I’m not entirely convinced this is even a topic that warrants much concern. You have no business discharging any firearm in a direction which could cause harm to an innocent person (see rule #4) and any cartridge that can penetrate deeply enough to reliably incapacitate a bad guy will also penetrate through multiple walls, televisions, and lawn flamingos. But does a 10mm actually penetrate much farther than service pistol cartridges?

Like most good questions, the answer is “It depends.”

The root of the misconception lies in the belief that more velocity always equals deeper penetration. That’s just not the case. Even when we consider only solids, penetration is a function of velocity and sectional density (weight to length ratio). That means that a 10mm bullet will penetrate less than a bullet of similar construction, weight, and velocity in .357 mag.

Then something unexpected happens when you consider jacketed hollow point defense bullets. After the point at which they begin to expand, they actually tend to penetrate less as velocity increases. The reason is that greater velocity means bigger and earlier expansion. That means that if you compare identical JHP bullets fired from .40 S&W or 10mm, the 10mm will tend to penetrate less.

 Recoil

It is true that a “nookular” 10mm load has fairly stout recoil. It feels a little like .357 mag but is softened and slowed a bit by the action of a semi auto so it is a bit of a longer push. Nevertheless, 10mm doesn’t really need to be loaded to mind blistering velocity to be useful for many applications. Yes, you’ll want velocity for reduced bullet drop if you’re using it to hunt in open terrain. Yes, you’ll want fast moving, heavy bullets with deep penetration for large animal defense.

If your purpose is personal defense against bipedal critters, though, not much is gained with the extra power.

There has been much lamenting about the dearth of “real” 10mm from the major ammunition companies but that isn’t necessarily a bad thing. Those factory loads are typically a little more stout than is possible with .40 S&W but not so powerful as to produce difficult to control recoil. They are actually very well suited for defense. Penetration and expansion are perfectly adequate without excessive recoil. The same can be done with hand loads.

Money

Well, you got us there. Kind of. It is true that you’re less likely to find 10mm on a Walmart or Big 5 shelf and if you do, it usually costs more than the common service pistol cartridges, but companies like Georgia Arms and Underwood Ammo sell full power 10mm ammunition for about the same cost as you’ll normally find .40 S&W or .45 ACP. If you can find it nowadays, that is.

In my neck of the woods, even during the darkest moments of King Zero’s ammo panic, Buffalo Bore 10mm ammo was on the shelf at Sportsman’s Warehouse. Not a single round of 9mm, .40 S&W, or .45 ACP could be found, but 10mm was available. You might complain about the price but at least it was available.

There is another dimension to cost, though. It doesn’t cost any more to reload 10mm than any other handgun round. You can use the same dies and projectiles as .40 S&W and some of the same powders work well too.

Too Much?

10mm seems to be a victim of its own ability. Can it have too much penetration? Sure, if you choose a load that penetrates too deeply, but you can do that in other calibers as well. Can it recoil too much? Again, if you choose a load that is not well suited to the purpose then that might be the case. But it doesn’t have to be. In my not so humble opinion, the real strength of the 10mm is not its raw power, but its versatility.

Anything the 10mm can do can be done better by another gun but I don’t think any other gun can do as much as the 10mm with a simple change of magazine. If you want to zap varmints or small game with a light, fast bullet that has less drop than a laser beam, it can do that. If you want 15 rounds of deeply penetrating hard cast bear defense bullets, it can do that. If you want a solid defensive pistol with moderate recoil and good terminal performance, it can do that too.

It’s not that the 10mm is too much, it’s that it can be too much if you choose the wrong load for the job. With its wide range of capability, though, you can probably find a load that is so perfect for your needs that even Goldilocks would be happy.

That’s my story and I’m sticking to it.

Do you shoot 10mm? Let us know why or why not in the comments.

Andrew Betts served with the Arizona National Guard for over 12 years, including a tour to Afghanistan.  Visit his YouTube Channel for more great shooting information.