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Is an AR-15 Appropriate for Home Defense? Part One: Penetration Issues

To find out how an AR-15 penetrates interior walls, I built some, then shot 'em up with a bunch of .223 Remington ammo.

To find out how an AR-15 penetrates interior walls, I built some---and then shot 'em up with a bunch of .223 Remington ammo.

Is an AR-15 appropriate for home defense? That’s a really big question, isn’t it? Way too big a question for a single article to address in adequate detail. So we’ll look at one issue at a time.

First, since AR-15 rifles cause all nature of mainstream media histrionics, we’ll consider the “high-power” issue, which in a practical sense, translates to penetration. If you torch off a .223 Remington or 5.56mm round indoors, will the building explode? Listening to the news, you might think so.

More rational, and less pants-wetting thoughtful consideration yields a different conclusion when we look at penetration specifically. If you shoot an AR-15 inside your home or apartment, and miss your target, will the projectile continue to pass through interior walls, exterior walls, cars, dump trucks, and eventually the nearest ocean before embedding itself deep under the sea floor?

These are curious questions. Being curious, I decided to build some very small walls and shoot them with an AR-15. I shall call them mini-walls.

I shall call them.... mini-walls. I built four in total, each with sheet rock on both sides.

I shall call them…mini-walls. I built four in total, each with drywall on both sides.

When considering home defense options, from strictly a penetration point of view, the basic question is: what will over-penetrate through walls, furniture, and your shiny new Ninja Blender? A heavier and slower pistol round, or a very light and fast rifle round?

The thing about light and fast bullets is that they tend to get upset–specifically, fragment or tumble—when they hit harder things like walls or furniture. Tumbling and fragmenting both result in a very rapid loss of velocity and energy, therefore a lightweight rifle projectile going somewhere around 3,000 feet per second may actually have less unwanted penetration than a pistol round traveling in the 1,000 feet per second range.

Before sharing results, I should present a couple of disclaimers.

  • I suck at construction, so if you are a professional carpenter, just hold your lunch down while looking at the photos of my mini-wall construction efforts. I’m only shooting them to pieces, not putting them in my house.
  • I didn’t paint the walls. This may sound trivial, but several coats of dried paint are hard, and likely to make some difference in the rate that lightweight, high-velocity bullets break apart.
  • The walls are close together. As you’ll see, some of the projectiles started fragmenting pretty quickly. If they had more time to spread out before hitting the next wall, I suspect they would have lost a lot of energy. Think of a shotgun pattern. When the pellets are still “clumped” together at short range, there’s more penetration than when they spread out to a three foot pattern a little further out.
  • I’m not a ballistic scientist. I just got curious, decided to do some basic testing, and share what I found. Do with the findings what you will.

With all that said, I looked at two different “interior wall” simulations. In one scenario, I used drywall (Sheetrock) only. I assumed the projectiles only hit drywall material of multiple walls. For the other scenario, I added a piece of 3/8-inch particle board between walls one and two—just to simulate junk inside walls like cross beams, furniture, or any number of other things besides wallboard that may be inside a home. All shooting was done from “indoor” ranges of five yards.

The first step was to establish some pistol round baselines. I shot both 9mm full metal jacket and 9mm Hornady Critical Duty 135-grain hollow point rounds through the walls—both with and without a wood barrier in the mix. I also shot a “standard” practice ammo full metal jacket .223 Remington round, in this case an American Eagle 55-grain projectile.

AR-15 Drywall penetration 4

Shooting through drywall only, the 9mm projectiles went right through all four walls and right out the back. So did the .223 Remington full metal jacket loads.

While both the 9mm and .223 Remington projectiles went through all four walls (eight pieces of Sheetrock), the .223 started to upset after passing through the second wall in the drywall-only test. As you can see in the photos, it went through walls three through four bumbling and tumbling—and losing lots of energy in the process. But the path stayed true, and the .223 projectiles were not knocked off-course.

The 9mm rounds? They didn’t deviate a bit and went through all four walls like butter. If I had four more walls, I suspect the pistol rounds would have gone through those too.

The .223 projectile started to tumble, as expected, after passing through just one wall.

The .223 practice ammo projectile started to tumble, as expected, after passing through two walls.

When I added a piece of 3/8-inch particle board to the mix, the .223 full metal jacket round started to tumble right away. And it never did exit the fourth wall. Again, the 9mm bullets went through all eight pieces of Sheetrock (four walls) and the particle board without upset or deviation.

Premium ammunition

With some semblance of a baseline, I wanted to try several .223 hunting and self-defense loads to see how they would react to interior walls and wood obstacles. This was not intended to be a test of specific ammunition performance, as each variety is designed for different purposes, but rather an observation of what would happen when various projectiles encountered interior walls.

Some of the loads tested against interior walls

Some of the loads tested against interior walls.

Of the five loads tested in this scenario, only the DoubleTap Ammunition 55-grain Nosler Ballistic Tip and Hornady 55-grain V-Max are designed to somewhat expand when they hit something. The Speer Gold Dot, Black Hills Barnes TSX, and Winchester Ranger loads are built to penetrate deeply and expand in a controlled fashion, so I expected those to go through interior walls without too much upset. Again, this was a curiosity exercise, not a performance test of one ammunition type against another.

You can see that the Barnes Ballistic Tip and Hornady V-Max projectiles started to break part, as designed, quickly.

You can see that the Barnes Ballistic Tip and Hornady V-Max projectiles started to break part, as designed, quickly.

As expected, the Nosler Ballistic Tip and Hornady V-Max projectiles started to break apart after passing through the first wall. The other three, again as expected, displayed more controlled expansion throughout. The Speer Gold Dot did start to tumble between the second and third wall.

All five loads passed through all four walls.

All five loads passed through all four walls. The Hornady V-Max and Nosler are top left and right, respectively.

So, using only drywall segments with no wood barriers, all five loads passed through four mini-walls. As you can see, the exit patterns of the Nosler and Hornady fragmenting projectiles show that those were heavily fragmented by the time they left—most likely having lost much of their initial energy.

As the DoubleTap Ammunition 55-grain Nosler Ballistic Tip and Hornady 55-grain V-Max displayed the least unwanted-drywall penetration, I wanted to re-introduce the 3/8-inch particle board barrier. Remember that the basic idea behind the wood barrier is to account for material inside walls or furniture in front of, or behind, walls.

Both loads displayed aggressive fragmentation.

Both loads displayed aggressive fragmentation.

Both loads started to fragment quickly. After passing through one wall and the wood barrier, the holes in wall number two started to resemble a shotgun pattern. By the time they exited the additional walls, it was clear that all that was left of the additional projectile was fragments.

Pieces and parts made it to the fourth wall.

Pieces and parts made it to the fourth wall.

So what does all this mean?

Again, we’re dealing with somewhat uncontrolled observation, but a few things stood out.

  • The pistol rounds were seemingly unaffected by the drywall and/or wood barriers. There was no observable deviation or fragmentation of the 9mm projectiles. You’d be safe counting on a pistol round to keep going, and going, and going. After all, premium pistol ammunition is designed to expand, and lose energy, when striking liquid-based targets—not walls.
  • The full metal jacket .223 rounds tended to tumble rather than break apart when they encountered barriers.
  • The projectiles designed for rapid fragmentation (Nosler Ballistic Tip and Hornady V-Max) did in fact do that. I wish I had gel blocks to see exactly how much energy remained. By observation of the fragmentation patterns, they were clearly losing velocity and energy. How much damage would they have done to a person at that point? I can’t say more than “less” than the pistol rounds, which were still humming right along.
  • Even though the .223 rounds start with a lot more energy, they tend to lose it quickly when encountering the barriers in this test.
  • You always have to worry about what’s behind your target. Nearly all of the rounds tested went through at least four walls, although some obviously came out the back end with a lot less energy than others.
  • If you live in an apartment, you may want to assume that only softer, interior walls stand between you and neighbors. In a free-standing house, I’m confident none of the AR-15 rounds would have made it through interior and exterior walls. Windows, of course, would alter that assumption.
The Hornady V-Max (top) and DoubleTap Nosler Ballistic Tip (bottom) are excellent home defense options if you're worried about over-penetration.

The Hornady V-Max (top) and DoubleTap Nosler Ballistic Tip (bottom) are good home defense options if you’re worried about over-penetration.

Before all this tinkering, I expected that some of the AR-15 rounds would blow up early and not penetrate multiple walls. Given that almost all did, that was a bit of a surprise.

Moral of the story? Don’t trust the mainstream media. Those high-powered, so called “assault weapons” may be safer than your average pistol for inside-the-home defense.

In upcoming articles we’ll look at issues beyond penetration that weigh into the decision of whether an AR-15 is appropriate for home defense.

Images by Tom McHale

Any views or opinions expressed in this article are those of the author and do not reflect those of OutdoorHub. Comments on this article reflect the sole opinions of their writers.
  • RichCalson

    Question. Why was there not a shotgun use at least once to compare the results? I know a lot of people, including me that have been lead to believe that a shotgun with #6 birdshot was your best home defence weapon. Granted a shotgun would not have the range as a hand gun or a rifle, but when you have ( asin my case) three young girls at home) a round going through more than one or two walls is not a good idea. I would appreciate any comments or questions. Comptec@hotmail.com

    • http://mygunculture.com/ My Gun Culture

      Hi Rich – Only cause of space, the shotgun test is coming now that I have these truly awesome wall frames built :-) Don’t tell any construction union bosses…

      That one will require two tests, i.e. at what range is birdshot still effective at soft targets AND the penetration thing. I suspect there is a balance there that I would like to find re: effective distances.

      • carl

        forget birdshot!! I’ve shot squirrels where the pellets were stopped by fur/hide. go with a load of 2-3/4″ 12ga packing 16 pellets of #1buck. that’s 16 .30cal projectiles at 1250fps. scratch one career criminal! (3″ load throws 24 pellets @ 1050fps)

    • Azbearhuntr

      I would research birdshot vs ballistic gel in general. From what I’ve seen even at a few yards away it doesn’t have the penetration needed to reliably put down an attacker, at least not a determined or drugged up one. At close range you’ll leave a nasty surface wound but depending on angles and range it’s shady. Just my two cents.

    • Old Texian

      Nothing wrong with a shotgun! However I would consider changing out the #6 birdshot choice. If someone breaks in, is drugged, wearing several layers of clothing I doubt that #6 would stop ‘em. Try some of the new shot defense ammo. Some of it is pretty mean.

  • Azbearhuntr

    Great test! A lot of people don’t understand the heavy and slow vs light and fast elements of bullets. It’d be interesting to have gel blocks in front and behind a wall pattern to see what happens when you hit your target. An easier way to test would be to place a chronograph behind the wall to see how much velocity is left. A small peice of 1/2″ polycarbonate could protect it from fragments.

    • http://mygunculture.com/ My Gun Culture

      You’re ahead of me too. I would have like to have gel blocks in between to see exactly how much energy was left after various wall hits. Future idea…

    • carl

      the ammo company engineers that design the bullets most likely have a ream of test results of every type. maybe they would make it available(?) possibly not, due to proprietary considerations. for instance, for defensive use(anti-personnel) it was my guess that varmint bullets would be better than hunting bullets. this was confirmed by a call to Remington. the trick is to select the right bullet that won’t “blow-up” on impact, but penetrate at least 1″-2″ before fragging or tumbling. a bullet suitable for coyote-sized animals would most likely fill the bill. my 2c’s.

      • Azbearhuntr

        Just remember the average depth to vital organs in a human is 6″, depending on angles the bullet may have to travel 12″ to get there. This isn’t considering a larger than average attacker or heavy clothing. Generally if a round is powerful and penetrating enough to reliably incapacitate a human it’s also going to penetrate walls. Study the angles of your house and likely shooting corridors to minimize the danger to others and train enough to minimize misses.

      • carl

        6″??? 12″??? where are you getting these figures? if you stuck a 6″ knife in my chest it would just about come out my back. i’m 5’10″/190lbs. i GUARANTEE you that if ANY weapon penetrated your body in a vital area to a depth of 3″, you would be in a bad way!
        i think you may be referring to recommended penetration on deer-sized game; way different.

      • Azbearhuntr

        I’m built the same as you I was basing that info on the average man…average these days is pretty over weight. You also have to consider angles you may encounter and your attackers body position

      • http://mygunculture.com/ My Gun Culture

        The 12″ figures are FBI standards for human targets and account for angles, extremities like arms / legs etc. Agree with your assessment of 3″ but only for a straight on, unobstructed hit. Start adding up, down, sideways angles and you get to 12″ or more really quick, which is why the FBI test protocols call for that.

  • Old Texian

    Great ammo study! Can’t wait for the shot articles.

  • Dogbreath

    Can’t wait for the next tests!

  • Paul White

    Thank you for your article. The following quote, from your article, was my “question-of-the-day” on my Facebook page, along with a link to your piece:

    If you shoot an AR-15 inside your home or apartment, and miss your
    target, will the projectile continue to pass through interior walls,
    exterior walls, cars, dump trucks, and eventually the nearest ocean
    before embedding itself deep under the sea floor?

  • fuzznutz

    He gets it from Gray’s Anatomy, the standard medical textbook. Where did you flunk out of med school?

    FBI duty load protocol requires no less than 12″ of penetration. Simply sticking a bullet in someone doesn’t necessarily get the job done. You have to break something they’re going to miss, and sooner rather than later (google for the “1986 FBI Miami shootout”).

    The point in shooting someone is to incapacitate them, to stop them doing the prohibited activity they were engaging in. And dead is the most reliable form of incapacitation. I can cite many instances of people being shot more than 10 times but continuing to function. And anyone with a functioning trigger finger is not incapacitated.

    The record holder (AFAIK) is Howard Morgan, who survived being shot 25-28 times (hard to count, the holes all sort of ran together) in Chicago, Ill., on 21 February, 2005 (google for details). He survived because none of the more than two dozen hits broke anything he couldn’t live without. On 9 August 2010, Angel Alvarez was shot 21 times by NYPD, and lived. The list goes on.

    So you can run with your little 3″ penetration theory if you want, if someone invades my home, I intend spattering hair on the walls.

    • J Brandt

      Fuzz, You are correct. The heart and great vessels sit around 6″-8″ from the rib cage, that in itself is around an inch thick. Add some adipose tissue (fat) on top of the ribs, or what part of the respiratory phase someone is in and you can easy get to the 12″ mark. You also have to realize that the ribs are really close together, and there is a really good chance that a bullet will first have to pass through a rib, and loose some energy before it hits a vital organ or great vessel. I didn’t get my information from Gray’s (though I have it), but from having my hands inside actual cadavers.

  • Jose Swenson

    #6 bird-shot within 15 feet. The longest average distance in a home is lethal. Remember, dick Cheney’s friend was at 25 feet and a pheasant load almost penetrated his heart though wind, a hunting jacket and shirt and his ribs.