Safety and Training

Bullet Penetration in Home Environments

Bullet path through a wood block

When choosing a home defense handgun, rifle, or shotgun, the gauge, caliber, and load are important considerations. If you are in a crowded area, this is important. If you reside in a rural area or the home is isolated, penetration of building material doesn’t mean as much.

2x4 stud with 9mm and .45 ACP bullet holes
The .45 and 9mm exited, but in this case the 40-grain High Velocity .22 turned and came to a stop.

Or does it? There may be family members in other parts of the home, and the shots cannot be called back once they are sent out.

The primary goal of a personal defense load is to penetrate the adversary’s body, do damage to vital organs, and cause a shutdown of the pressurized system. Only blood loss will cause this shutdown. The responsibility of the home defender is to strike the target.

Firing when you do not have a reasonable expectation of hitting the target isn’t a responsible action. Being human, you may miss, and you should know what to expect when a bullet connects with common building materials.

There is an interest expressed by defensive shooters in the use of cover, and I felt I should take that track as well in my testing.

What types of building material will give the homeowner cover if they are under fire? After all, bullets go both ways. Hardening a home against gunfire is a daunting proposition. If you elect to pour concrete between the walls, be certain the foundation will hold the weight.

Since abandoned homes in a safe area that the owner is willing to allow me to shoot to pieces are rare, I constructed simulated walls and fabricated test objects. Next I fired a few hundred rounds of ammunition and destroyed a truckload of structures.

Drywall from a home with several bullet holes
Wallboard doesn’t stop most projectiles.

In the end, I discovered loads that are very attractive choices for home defense. You cannot sacrifice penetration by choosing loads that blow up on heavy leather jackets or fail to penetrate to the vitals, but neither do you wish to use a Magnum hunting load in the handgun.

The primary focus was on the handgun, as the handgun is always with us, but I studied rifle and shotgun performance. The problem of overpenetration in the home or apartment has been discussed many times. The fear of a bullet carrying far past the area of a gun battle is real.

Wounds received by innocent persons happening to be in the wrong place at the wrong time are not uncommon. However, most of these occur in the open or on the street and are a result of missed shots rather than overpenetration. The great majority is the result of actions by our protein-fed ex-con criminal class rather than honest citizens. Incidents involving homeowners firing through walls or a bullet exiting the home are less common.

The majority of armed citizens are mature, conscientious individuals. I looked at the whole picture and tested ammunition from several angles. Homes differ in construction, and at best a general understanding of home penetration parameters was gained. Responsibility for every round fired is a concern and safety from a bad guy’s bullet another.

.223 Remington bullet fragments
Lightweight .223 bullets stopped short in wallboard, and many fragmented.

The first solution to the danger of an overpenetrating bullet exiting a home is to hit what you are shooting at, as I keep repeating. Carefully place a hollowpoint bullet into the assailant to let it expand properly and there will be no overpenetration problem. Know the distance between one occupied structure and the other.

Since we usually fire at an angle slightly up or down and seldom perpendicular to the target, the chances are the bullet will come to rest in something before it reaches an occupied home. A studio apartment with thin walls is another matter.

Hopefully, the burglar will present himself to your view and enfilade fire will get his attention. If he is in defilade, however, and under cover, you may need the ability to penetrate cover rather than limiting penetration.

There have been ridiculous cinema depictions of felons using a chair or mattress for cover. Bullets zip through these constructs, but some furniture may be heavy enough to turn a bullet. Will you be engaging in wall stitching in the home? Are there bullets that expand well in a body and stop short in home material?

Fiocchi 40-grain V-Max ammunition box
The Fiocchi 40-grain V-Max is an inoffensive home defense round.

Many high-velocity hollowpoint bullets will expand in the body, true, but when they hit the wall the bullet nose plugs and they penetrate like a full-metal-jacket bullet.

I noted that every test program in the popular press was inconsistent, with every author having a different idea, including some of the work I have done—after all, I learn things as I go along. One of the considerations never mentioned in the popular press is the existence of firewalls between walls in apartment complexes. (Older buildings may not have them, but let’s hope you live in a dwelling with firewalls.)

Stairwells and common hallways are an important consideration for the defensive handgunner. Another consideration is the difference between high-speed, light bullets and heavy, low-speed bullets. Drag is a slowing force that seems to work more quickly on fast-moving, light bullets. Heavy bullets, even when moving slower than light bullets, tend to penetrate more, as is the case with the 147-grain, 1,000-feet-per-second 9mm versus the 115-grain, 1,200 fps 9mm and the 230-grain, 850 fps .45 versus the 185-grain, 1,100 fps .45.

I tested a representative sample of handgun rounds against materials including pine board, drywall, cinderblock, and brick and added whatever I could come up with. The information obtained is interesting.

Hardened board with .45 caliber bullet hole
The author shot this old hardened board with a .45, left; 9mm, center; and .22LR, right.

Common sense tells us that a loading by one maker or the other will probably perform similarly to the test load in penetration if not in expansion, such as 115 grains at 1,200 fps in 9mm. Since the nose closes up and the bullet penetrates, a presumption is often made that only velocity and weight really matter, not bullet design. The same goes for 9mm full metal jacket or .45 ACP hardball, with one brand similar to the other.

This is actually true when it comes to FMJ loads but not true with JHP loads. A wide-mouth hollow-point such as the 115-grain JHP used in Buffalo Bore’s +P 9mm load breaks up rather quickly when fired against cinder block and doesn’t penetrate as much in wood as the slightly different Buffalo Bore +P+ load. The +P+ load uses a bonded design. The bullet stays together, as is the intent.

With the development in bullet technology during the past decade or so seeming to focus on bonded-core bullets, we need to carefully appraise our choices. Do we really need a bullet with high penetration against felons behind cover? Are the felons likely to be bundled in heavy clothing?

Bob Campbell shooting a 12 gauge shotgun at the shooting range
The 12-gauge shotgun is a formidable weapon that destroys home material easily.

Bullets with less gelatin penetration are less offensive in home penetration. I stand by the need for greater penetration in defense loads—at least on the level of 10 to 12 inches in water or gelatin—but it is clear that bonded bullets are designed for penetration of sheetmetal and window glass and perform as designed. Whether this is desirable is up to the homeowner.

In this test, the exactness of what we accomplished is respectable, but the great, broad, general conclusions of the test are also important. Judging by my experience in gelatin and water testing, loads that penetrate 12 inches of gelatin or a similar amount of water will not have sufficient energy to be dangerous and penetrate wall material once they penetrate a felon’s body—after all, they should be expanded. The real difference in safety is hitting the target.

Never use roundnose lead or full-metal-jacketed bullets for home defense. While the .45 ACP 230-grain FMJ is an effective anti-personnel load, a JHP bullet is more effective. I did not test ricochet, for safety’s sake, and neither should you. But among the few scares in the program was when RNL bullets bounced a bit when fired into hard wood. Even the .45 ACP, let alone the .38 RNL, will ricochet off a hard gradient.

hardened board shot with a .45 ACP 230-grain FMJ loading
We shot this old hardened board with the .45 ACP 230-grain FMJ loading.

Our Results

At one time, pine boards were the testing material for handgun bullets. After all, with RNL or FP lead bullets the FMJ expansion wasn’t a concern but power and penetration were. Around 1900 or so, pine board testing was commonly used by ammunition companies to illustrate the effectiveness of a handgun loading. Today, we might test pine boards in order to understand wall stud vulnerability to bullets. However, also understand that the studs in a wall will be facing rather than lengthwise, but just the same, this test is valid depending upon the bullet angle.

For our tests purposes, the pine boards were set up an inch apart to allow parts of the boards to be separated from the bullet as it flew through the boards. All boards are not the same, and a quarter-sawed board will be more dense. A quarter-sawn board is quartered lengthwise, and there are wedges at right angles to the center of the original board. So—different boards, different results.

Another unscientific but interesting test of hardened four-inch-thick boards was conducted. In this case, the .45 ACP loads—mostly 230-grain ball—not only fully penetrated, it was obvious that they were pushing a large wound cavity. There was actually a recognizable lengthening of the cavity as the .45 ACP bullet pushed through the board.

Brick Constructs

Bricks are found in a single layer attached to the outside wall of a frame building. Next are wall studs, plywood, and insulation. I shot bricks stacked in groups or four or more. In a true home environment, the shot is coming from the inside out in the case of a missed shot and would hit the wallboard first. In a drive-by, bricks are hit first. When bricks are in sections, mortar holds them together and the support of the structure keeps them resilient. In firing, a pockmark was seen on the bricks and nothing more with the calibers below .38 Special.

small well house
This small well house was purchased at a yard sale. The construction is similar to home material, and the boards were treated to resist the elements.

Beginning with the .38, damage began to be evident. The 9mm and .45 ACP bullets damaged the bricks but hardly enough to go through. After two to four shots, the bricks were cracked. The .357 Magnum revolver and the .223 Remington rifle were very similar, bringing into focus the often-quoted remarks of early users of the Magnum: “It is like having a rifle on the hip.” The .357 and the .223 each took a large chunk out of the brick and often broke it with a single shot. We found that one to two rounds in the same spot often broke up the brick and crumbled it.

In the case of cinder blocks, the .45 ACP JHP just made a pockmark, and part of the bullet penetrated on the first shot. The fast-stepping 9mm was much the same. The .357 Magnum 110-grain loads did no more. The 1,400-fps .357 Magnum struck the block three or four times without great effect.

The 158-grain JHP .357 Magnum load made a large cavity in the block with the first shot and an opening into the hollow between the two sides of the block with the second shot, sometimes with the first shot. The third shot with the Magnum shattered the cinder block.

A slow-moving 158-grain .38 Special SWC at 850 fps did more damage than the 110-grain .357 Magnum. The 230-grain FMJ .45 broke up the blocks with very few shots. Moving to the 12-gauge shotgun, double-ought buckshot produced spalls (pockmarks) without penetration and bounced like mad in some cases.

We took at least a 50-foot setback when testing and were glad we did when this unexpected event occurred with buckshot. The buckshot balls flattened on cinderblocks and bounced back 10 to 12 feet. This would not be the load of choice in a crowded environment with a cinderblock wall. You could easily shoot a felon and yourself with one shot. Shotgun slugs demolished cinderblocks with a single shot.

The next step was wallboard penetration. It should be no surprise that bullets and buckshot go through wallboard—it’s just paper and clay. As one of the raters noted, there is no magic bullet that will not penetrate in the home and relieve you of the responsibility of aiming straight and not engaging in spray-and-pray. Every shot must be carefully aimed.

Just the same the results are interesting, and it is obvious that some cartridges are better than others. We built a construct of wallboard with a total of 12 boards. They were not complete walls, but in some cases simply 12×12 sections nailed to boards—12 wallboards, six walls. Then we had to rebuild them several times. This comes out to six walls with one board in and one board out. The results are interesting.

Some Individual Loads

Man firing a handgun at an outdoor range
A lot of testing goes into this type of research.

.223 rifle

During our .223 ammunition tests we found that many .223 rifle rounds are best suited for varmints. They stand an excellent chance of breaking up on light cover, a belt buckle, or heavy clothing. So, we are beginning with a round that needs a bullet of 50 grains or more to be effective in personal defense.

While the .223 may be very effective in home defense, the question of muzzle blast is harrowing. The blast (the .357 Magnum is another offensive caliber) is potentially deafening, with permanent effect on our hearing. If you have the carbine and your Wolf Ears at home ready, you are way ahead of the game, but few will do this.

The .223 loads bear special attention.

Fiocchi 40-grain V-Max

This load began to fragment in the first wall of the wallboard testing. When the second section of the first wall was penetrated, the bullet was obviously fragmenting. Some pieces made the second wall, but none fully penetrated the fourth board. Most of the 10 rounds fired stopped in the third board. This is a good, safe bullet for interior use, but it may not have sufficient penetration for defense.

Black Hills 55-grain JSP

This load surprised us. We were expecting more, but it penetrated the third wall—six sheets—and fell across the next wall in fragments. That is still three walls but less penetration than some of the pistol rounds.

Black Hills 60-grain JSP

This is a highly recommended service load. This load ran right through all 12 sections. Since the 55-gr. JSP load was a good personal defense load and penetrates less in wallboard, it would be the recommended loading.

Shotguns

12 Gauge Shotgun

If anyone doubts how awesome the shotgun really is, this test is an eye-opener. Wallboard was blasted to pieces by most of the loads tested. Recoil is there, but the shotgun has great wound potential. Some thought should be given to this gauge and the loads. The buckshot loads potentially go through a lot of home material. On the upside, few antagonists struck with a load of buckshot will need a second hit.

Winchester 7½ birdshot

I have never tested birdshot for personal defense, so I had to do a few runs on water jugs to be able to intelligently comment on this loading. It has been recommended for home defense but obviously without a lot of testing. The result was poor in water testing—4 to 6 inches of penetration with only one or two pellets exiting the first water jug. This would be perhaps 4 inches of penetration in gelatin and not enough penetration for personal defense. In wallboard, this light shot penetrated two boards (one wall) and peppered the third board.

Winchester Reduced Recoil 00 Buckshot

This load penetrated five walls, 10 boards on demand.

Winchester #4 Buck

This load penetrated seven to eight boards and usually peppered the ninth board. It is a reasonable choice but an inferior answer to 00 Buckshot.

Federal 12-gauge TruBall One-Ounce Slug

This penetrated all 12 boards easily.

Bullet Penetration in Home Environments — Summary

The .223 isn’t offensive for home defense, no questions there. With the proper loading, the .223 may just be the ideal choice. Most handgun loads are similar in performance. The fast-opening JHP loads that demonstrate gelatin performance of good expansion and penetration of 12 inches are best for home defense overall. Loads on the long end of penetration will also penetrate on the long end in home materials.

The results of this tests show that 9mm, .357 Magnum, and .45 ACP JHP bullets are probably the best choices for home defense. FMJ and heavy hunting loads are overpenetrative for home defense use. In long guns, the .223 rifle is superior to the shotgun as far as safety goes. Still, the shotgun offers a devastating wound for those who have the proper scenario for its use.

Do you have a favorite load for home defense? What penetration testing have you done? Share your answers in the comment section.

The Mission of Cheaper Than Dirt!'s blog. "The Shooter's Log", is to provide information - not opinions - to our customers and the shooting community. We want you, our readers, to be able to make informed decicions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (21)

  1. Bob, thanks for your time in testing loads and writing this article.
    I have a good friend who recently spent a full month at Quantico FBI training school. One very amazing stat he shared: when there is a threat and our adrenaline kicks in, even the most seasoned law enforcement officer who regularly goes to the range will only hit the target 30% of the time! That seems incredibly poor. The scientific reason is that our “coarse” motor skills automatically take over and our fine muscle motor skills go out the window when we have an adrenaline rush. It’s a physiological thing that we can’t control. Secondly, a bad guy can cover 20′ of ground before his body will “feel” the hit and he goes down. More than 20′ if he’s high on drugs.
    My take away is that a defender should fire as many shots as practical, as quickly as possible, aiming for large body targets, all while keeping track of his backdrop.

  2. Reading the intro, I was excited to see where this article would go. But a lot of the methodology is either not given or unclear due to the ambiguous language. And a lot of your conclusions are either dubious, or I heartily disagree with.

    No, “common sense” does NOT “tell us that a loading by one maker or the other will probably perform similarly to the test load in penetration.” because there’s no enforced standard that ammo makers have to follow, even when using the most common bullet weights, in term of minimum powder load or muzzle velocity ). If you’re trying to write an authoritative piece on the matter, you have to show empirical tests and data, not appeal to “common sense.”

    When you say you “were expecting more” from the 55gr .223, did you mean you expected it to go through more layers of sheetrock? You expected it to perform better for this test and go through less? You mention the muzzle blast concern about .223 indoors, and that is very true of course. Did you look at any defensive specific loadings for .223? Any hand loadings to try to find a good balance between noise, power, and penetration? Did you test any .223 carbine alternatives, like 300 BLK or 6.8?

    What do you mean #4 buck is an inferior answer to 00? One 00 discharge would be able to go through an entire house, excepting the exterior walls maybe. If you’re looking for loadings without excessive penetration, it would seem 00 would be completely disqualified. To then say #4 is inferior, despite it penetrating less and still having lots of lethal potential against intruders goes against your purpose here.

    And saying birdshot isn’t powerful enough to stop an attacker means you looked for the answers you wanted, not what was in front of you. It barely makes it through a single wall, but from 20′ or less ( the range you’d be shooting in a home defense situation ) it will indeed put the hurt on an intruder. If anyone wants to see some far more scientific tests on shotguns for home defense, and what kind of loadings to consider, search up Paul Harrell. A load between #4 buck and #6 birdshot is usually a great balance for the task. Better yet, get it in 20 gauge for a lighter weapon with much lower recoil. Perfect for those that may not be able to handle a 12 ga.

    And Phillip, the argument that storing a loaded pistol is somehow safer than storing a loaded shotgun or carbine is preposterous. The number of quick access locking cabinets available today makes it perfectly safe and viable to have a long gun loaded and ready to go.

  3. I beg to differ on .223 breakup. With my colt 20 inch barrel AR I fired at a steel target holder for pistol targets. drilled two holes in 1/8 steel plate. The funny thing is the .223 drilled thirty caliber holes. And no there were no holes in the target until we fired at it. We thought the .223 would bounce off. Not so. Later tried a piece of spring steel that someone had used as a penetration test. There was an armor piercing tip 30-06 bullet nose sticking partially through the steel. Tried the .223 55gr ball. no penetration but a respectable spall and crater. Still have the spring and may one day try .223 armor tip.

  4. I use skeet shot in my 12 gauge to prevent over penetration. Thoughts on how effective that would be? Should I switch to a low recoil buckshot? We have fire walls, lots of brick, but I really don’t want to accidentally shot my neighbor.

  5. Great article and information. It’s good to have data on penetration through real world materials.

    I did some ballistics testing a couple years ago through phone books taped in a group back-to-back. I had a total of about 15 inches of paper depth. Here are the penetration data (inches of penetration): 22 HP = 2.1″, 9 mm FMJ = 4.5″, 9 mm HP = 3.3, 308 Win Steel FMJ = 11.3″, 308 Win brass HP = 8.1″, 7.62×39 Steel FMJ = 8.5″, 7.62×39 Brass FMJ= 6.9″, .223 green tip = 8.1″, .223 HP = 7.3″

    I also calculated the cubic inches of material displaced using the entrance hole diameter and the end of path “exit” hole diameter (used geometric formula for truncated cone formula). The values are (cubic inches): 22 HP = 0.45, 9 mm FMJ = 1.8, 9 mm HP = 1.9, 308 Win Steel FMJ = 5.9, 308 Win brass HP = 7.6, 7.62×39 Steel FMJ = 3.2, 7.62×39 Brass FMJ = 2.1, .223 green tip = 1.28, .223 HP = 2.1

    Ken

  6. One of the most popular defensive rounds on the market is the Hornady XTP, which is what I carry in my EDC in 124 gr. 9mm and what I keep in my nightstand gun, also 124 gr. 9mm. On the rare occasion when I carry one of my 1911’s, it’s also loaded with 230 gr. XTP. I’ve found it to feed and cycle reliably in every gun I’ve tried it. I’ve seen videos of gelatin tests on various calibers of XTP, but I’ve never seen any on penetration of building materials, nore have I done any tests myself. Did you use any XTP rounds in your testing? If so, what were the results?

  7. The best gun for home defense is a handgun that one can shoot well. Keeping a loaded rifle or shotgun with family members nearby is dangerous when children are present and socially repugnant to others not to mention visitors. The pistol can be kept nearby, ready and out of sight. There are a number of good bullets available today for home defense. Find out what your local, state and federal police are using and you are close to the ideal. Have a flashlight available and if weapon mounted, preferable as it frees up a hand. Then practice as often as money and time allows.

  8. Interesting and informative article. One load I would have liked to have seen tested would be high brass 4’s or 5’s in 12 gauge as well as the 71/2 birdshot. My assumption being that since many Turkey hunters use these loads, it must be a higher power load, obviously with larger pellets, hence, different results.
    Another point of interest would have been testing on plaster walls, since many older historical homes have plaster or a combination of dry wall/plaster walls. However, I realize you put in a lot of work for your tests, and I appreciate it. Maybe a follow-up article with these other test variables one day?

  9. Many, many years ago, in the age of magazines, the problem of over-penetration would frequently come up. One thing I remember was hand loading shotshells with dimes. In this day and age we have a couple of handguns chambered for 45 long colt/410 shotshell. I would have like to see a test on the 410 shotshells loaded with copper dics and buckshot. While I don’t think over-penetration would be a problem, I question their ability to stop an intruder.

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