What is overpenetration?
Overpenetration occurs when a bullet passes through its intended target and continues traveling with enough energy to strike something beyond it. In real-world shootings, this is far less dangerous than missing the target entirely.

Stop worrying about overpenetration—and you should too.
In the world of home defense, few topics are discussed with more fear and less clarity than overpenetration. Here are five reasons you should stop obsessing over it and start focusing on what actually stops threats.

1. Get Your Priorities Straight
   
   Your first and second priority in a gunfight should be the survival of yourself and your family. And while right now you are probably thinking you can save everybody like Superman, when 3 thugs kick down your door and you see guns in their hands, where your neighbor is right now will be of no concern to you. And it shouldn’t. The topic of over penetration is one I always found so strange. It always seemed like the scenario that gets painted is that the neighbors become priority one, while oneself and one’s family become a distant second..
   
   Now I know what you are thinking; I am not worried about my neighbors, I am worried about my kids sleeping in the next room. Fair enough and I’ll go over this more in depth, but here is my short answer. You cannot save your family if you are dead. and don’t go John Rambo and attempt suppression fire in your 3-bedroom apartment.
   
   
2. You Can Still Follow Basic Gun Safety
   
   Basic gun safety: Be sure of your target and what’s beyond it.
   
   You really do not have to break this rule to be successful in-home defense. As previously mentioned, you are worried about your kid sleeping in the next room over, right? In addition to not doing mag dumps or suppression fire in the home, consider this – ID what you are shooting before you fire and if you aren’t sure about destroying what is in front of your muzzle, do not shoot.
   
   Now if your target is in front of something you don’t wish to destroy, let’s move onto the second topic.
   
   
3. Missing & Overpenetration Are Not The Same Thing
   
   So your target is in front of a wall, which is in front of something dear. Let’s be very clear what we are talking about. Missing the target and having a bullet penetrate the wall and beyond, is not the same thing as having a bullet penetrate our unwelcome late-night guest and penetrate beyond.
   
   It is imperative to differentiate, they are not the same. Hitting the ghoul is the purpose of utilizing a gun to defend oneself, which is why no one wants to talk about this type of over penetration.
   
   Missing the shot completely and having the bullet penetrate the wall is not over penetration, it is just missing. The bullet penetrating the wall is just what bullets do.
   
   Which is why you need to be sure of your target and the shot. And why you should seek good training.
   
   
4. Don’t Over Correct
   
   The biggest side effect I’ve seen from folks worried about over penetration is the propensity to over correct. The over correction typically manifests by someone making a poor firearms or ammunition selection and then concluding that they chose it because they don’t want to penetrate drywall.
   
   In other words, they have made over penetration their primary consideration and chief priority over making a selection that can most quickly end the threat.
   
   Typically, in doing so they have not only put aside the most effective firearms and ammunition in this scenario, but they may also not have the over penetration security they originally intended to gain. Some folks would believe that a 9mm or a 45ACP would not be a drywall penetrator but they certainly are. Some folks may tell you that a 22LR wouldn’t penetrate an interior wall, but they wouldn’t just be wrong, they’d likely be outgunned. Worse yet, they may not consider what is beyond their target as a result of incorrectly assuming their rounds aren’t capable of penetrating their interior walls.
   
   I’ve even seen some so desperately worried about over penetration that they buy the notoriously poor stopping rounds like snake shot or birdshot. This leads to my next point.
   
   
5. Penetration Is Good
   
   No pun intended, but penetration is good. Penetration is what allows the projectile to make their way through the clothing, flesh, muscle, fat and get to the vital organs and stop the threat fast.
   
   During the infamous 1986 FBI Miami Shootout, shooter Michael Platt was shot by FBI Agent Jerry Dove’s 9mm in his upper right arm which went on to penetrate his chest. The 9mm stopped an inch away from Platt’s heart, this proved to be fatal but not immediately, nor did it knock Platt out of the fight. Platt when on to shoot two more agents and was later killed attempting to escape.
   
   The point is, too little penetration can extend the fight even if you get a good hit.