The Myth of “Over Penetration”

This is a guest post by Andrew BettsOver Penetration

I didn’t stutter. Garbage. Baloney. Hooey. Hogwash. The notion of “over penetration” has been circulated a great deal. It’s been repeated again and again by gun counter know-it-alls and 1st Interwebz Division commandos, but there is virtually no reason to be concerned about it. I am fully aware that these words will cause some folks to get rather emotional, but stay with me.

To the best of my knowledge, there has never been a single instance of a bullet fired by a legally armed homeowner during justified use of force that passed through the intended target and harmed an uninvolved third party. There have been multitudes of cases where projectiles that have failed to penetrate adequately have failed to stop an attacker. As we discussed recently, birdshot is a regular offender in that regard. Under penetration routinely fails to stop attackers in a timely manner and can most certainly get you killed.

“Over penetration” is total nonsense, but under penetration is very real. When selecting a load for home defense, alien invasion, or just in case of a rainy day, it is wise to select ammunition that can penetrate adequately, that is a minimum of 12 inches, with deeper being better for the most part. At the very least, you need to be able to reach deeply enough into the bad guy to stir up his important bits, even if his arms are outstretched holding a weapon and your bullet has to traverse eight inches of forearm before even reaching his torso. But it may also give you a bit of confidence to know that you have the ability to shoot through most anything that could be between you and the bad guy, as we see in this breathtaking high speed video of 7.62x51mm NATO.

To be fair, 7.62x51mm may be a bit much for home defense because of weight, recoil, and muzzle blast, but it is comforting to know that you have the power to get the job done. Full power rifle cartridges are essentially obsolete for use in infantry individual weapons because it is far more valuable to be able to carry double the ammo, but the home owner doesn’t have to march fifteen miles with a 70-pound rucksack before the fight and he probably won’t have the opportunity to change magazines. The matter is likely to be settled with relative quickness, one way or the other. A 20 round magazine is probably all you’ll need to win the fight and if you don’t win, it will probably last the rest of your life.

Still, there is a sound argument to be made that a lighter recoiling cartridge like 5.56mm, 7.62x39mm, or .300 AAC is better suited to the job of home defense. Whatever cartridge you choose, adequate penetration is absolutely critical and hand wringing about “over penetration” is a waste of time.


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.

Video and Photo Credit – Buffman R.A.N.G.E. @YouTube


  1. Your theory needs to be better qualified. Most pistol rounds will not over penetrate when shot into the torso of a human. However it will pass cleanly through extremities. If your unsure of this then ask the people that clean up after suicides and see if they have to clean up brain matter from a pistol shot to the head. Almost ever caliber of center fire rifle ammo will make a clean pass through of a human body with most bullets. When they exit they will do so with enough velocity and energy to penetrate a second target. An AR with Nato Ball ammo shot into a human at 10 feet WILL exit. The shooter must be aware of his target and background when firing a shot and be prepared to own whatever that bullet strikes once fired.

    Home defense weapons should be pared with ammo that limits complete penetration of the intended target. Pistols with rapidly expanding hollow points or shotguns firing shot are more than adequate for home defense.

    Your argument is understated. Ballistics will more than back the notion that a pass through of a modern rifle cartridge is a given on a human target. And almost all hunting rifles are guaranteed to. Your argument is careless in making an uneducated gun owner believe he does not need to be concerned about where his bullet will go once it exits the target. If that get a well meaning homeowner’s kid killed then are you prepared to defend your argument.

    If you do not believe this possible contact me and we will set up a real world shoot through ballistics gelatin and a couple pieces of sheet rock. Your video above proves the point and 5.56 Nato Ball round will do close to the same and that is on a cinder block not a soft human target.

    Be responsible in your reporting. I am all for owning guns of every sort and defending myself. I hunt will rifles and am prepared to shoot the bad guys with a 12 gauge and bird shot. At ten feet feet he will be unmotivated to continue after the first shot and the second will be right behind it.

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