Drywall penetration, part deux


Guns and more
January 20, 2011, 09:52 AM
There was a post about a week ago concerning drywall penetration.

The discussion centered around whether .223, 12 ga., or a .45 would penetrate more.

I opined that the .223 due to it's high velocity, would penetrate more.
However, I was informed (including a mod) that it was EASILY provable that
the .223 did not penetrate as much due to the bullet fragmenting.


Okay, I never considered that.

But, to my surprise, almost the same topic appeared on another forum where the question of a .223 penetrating brush was considered.

Surprise! The Box of Truth? has evidence that a .223 does NOT fragment when going through a maze of dowels.

My conclusion? It's phony. You can have it both ways if you choose the results you want first.

If you want the bullet to penetrate less, you select a .223 that will fragment, but not a .45.
If you want the .223 to penetrate more (as in the dowels), you select a round that does not fragment.

Apples and oranges will always prove nothing.
Am I wrong?

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Deus Machina
January 20, 2011, 10:23 AM
No, you're not wrong. And the BoT was most likely testing rounds that were designed to do what they wanted them to do. IIRC, the drywall test involved 'home defense' and varmint-hunting rounds, and the 'brush' test used more solid hunting or FMJ rounds. No point in testing a round designed to upset easily through a test to prove that the appropriate rounds wouldn't, right?

Of course, it would have added credibility, to reiterate that certain rounds shouldn't be used in certain circumstances. And the BoT really doesn't ever claim to be the be-all, end-all source.

The big (and less obviously spoken) test was whether a .223 designed to fragment easily would fragment through drywall, as opposed to a .45 or 12-gauge.

The plus side of .223 is that it is possible to find one that fragments in drywall--not that I would trust it every time--while anything you can run through a shotgun or handgun that will actually stop someone, doesn't have the velocity or light weight it needs to upset like that, so treats drywall like so much paper.

The thing to remember is that the Box o' Truth guys do try to recreate these situations, but there's nothing like actual field results.

January 20, 2011, 11:11 AM
For home defense a 12 or 20 gauge with #5 or #6 lead shot, basically a turkey load, is ideal. At a normal home defense distance the perp is just as dead as if you had shot him with buckshot, a .45, or a .223. There is less mess to clean up (Yes you are responsible for whatever the coroner doesn't take with him). And there is very little risk that any pellets that do penetrate a wall will have enough energy left over to cause harm.
The only down side is that you may annoy the medical examiner who has to pick all the pellets out of the dead gutter snipe you just sent him.

Guns and more
January 20, 2011, 11:53 AM
As far as what chaps my bacon is that certain people said, "It is EASILY provable that .223 won't penetrate as far as .45". What they didn't say is, "If I can stack the deck."

Since the discussion was about using a .223 for home defense, I feel they gave out dangerous information, and encouraged people to use a .223 for home defense when it might a bad choice. Had all the ammo been frangible, it might have turned out differently.

I like this site because of the vast wealth of knowledge.
I hate to see it tainted.

January 20, 2011, 03:00 PM
Nowadays, you can get rounds that will fragment in almost any caliber... if that is what you want. I think the caliber factor is far less pertinent than cartridge/bullet design here. Heck, a .22 LR plated round-nose will go through 6-10 sheets of drywall where a pre-fragmented .223 will stop long before. Again, it has little to do with caliber choice.

January 21, 2011, 09:42 AM

In a gunfight, y'all go ahead and pick your 1911's, I will go for the AR with armor piercing rounds.

January 21, 2011, 09:49 AM
I think come springtime I'll bring some scrap drywall pieces to the range and find out some answers for myself. Maybe even build some framing like a real wall out of scrap 2x4's. Then fire away and see what happens.

January 21, 2011, 10:03 AM

There ... I found it.

Guns and more
January 21, 2011, 11:27 AM
I think come springtime I'll bring some scrap drywall pieces to the range and find out some answers for myself. Maybe even build some framing like a real wall out of scrap 2x4's. Then fire away and see what happens.
That's what the test did. They took two pieces of drywall , maybe 2'x3' nailed to a stand made of 2"x4"'s to replicate a standard wall. It was an excellent experiment. Then a few pieces of drywall farther down range. Then all science went out the window. It would have been better if they had several of these setups, but instead, they fired multiple calibers at different areas of the drywall. In some cases they missed the third drywall, and hit the ground.
Had they used comparable ammo in each test, It could have been a great experiment.

In real science a high speed camera would record the bullet penetrating the drywall.
I understand this was an amateur test, and we should not draw too many conclusions from this.
I will go for the AR with armor piercing rounds.
You don't live next door to me, do you?


There ... I found it.
That's not the one I saw quoted, but if the ammo is the same, I'll except the results.
The conclusion is that all penetrated all 12 pieces of the drywall, so they moved to plywood.
12 pieces of drywall is enough for me. All will penetrate standard walls, and your neighbors walls too.
Since studs are 16" apart, chances of hitting one are slim.
So, be aware of where your bullets may go.
(Yeah, I know, you never miss.)
This is the test I'm criticizing. Read it with a critical eye and you'll see the problems.

January 21, 2011, 01:16 PM
1/2'' drywall as it is used in residential applications is virtually no barrier to penetration as far as firearms are concerned. 'ell, even a lowly Red Ryder BB gun will penetrate standard wall drywall. Of course, when multiple layers of drywall are placed sandwiched together there will be much less penetration, and may fragment high powered bullets, but this compares little to how drywall is used in modern construction.

January 21, 2011, 03:28 PM
Sure, penetration of building materials could be a hazard in the off-chance of a SD shoot, but, to be fair, this isn't something we encounter daily, unless we
live in Beirut.

I'm not going to let the possibility of an encounter with some bean-brain
skew my choice of a favorite caliber.

I'd be more inclined to look to safety loads.

January 26, 2011, 12:19 AM
It has little to do with the caliber. and more to do with the design of the bullet. FMJ's will penetrte farther than lead, JHP's or specialized ammo. There are steps that you take in any hobby. Learn the differences in the types of bulletts. not the calibers. My powerball corbon ammo will drop someone as fast as my 45 hydrashoch, but if i used FMJ ammo in my 9, it would penetrate farther than my 45, "most times". You want 12-14 inches or penetration and full expansion as fast as possible. The 45 will expand the 9mm should with good HD ammo. But the 45 would be my choice if I had to go into a house after a guy or he was in mine. I would sacrifice 2 rounds to have the 45 round.Look at the utube videos on speed vs expansion, and wound cavitys. The shock and wound channel is a big part. Plus I carry 3 mags. So a reload is not a big deal.

Jim K
January 26, 2011, 12:48 AM
Hi, Kenneth,

"For home defense a 12 or 20 gauge with #5 or #6 lead shot...is ideal...[and] there is very little risk that any pellets that do penetrate a wall will have enough energy left over to cause harm."

Have you tried that, Kenneth? How about some more information, like the distance from the muzzle to the dry wall? And the shot size? And the gauge? Did you use 1/2" dry wall or the now more common 3/8"? And exactly how did you determine that the "left over" energy wouldn't "cause harm"?


January 26, 2011, 01:12 AM
Assuming one chooses a sensible load for HD purposes for said AR...then yes it should penetrate less than a 9mm-.45 hollow point. I'd be OK with 'bout the same and take the increased power, accuracy, payload and ergonomics (that and a nice Aimpoint and weapon light).

I think over penetration concerns are way overblown. The first priority is to hit the threat with a load that will reliably stop the threat. That's job #1 and not a job I'd trust my families life to bird shot with. So, high quality 9mm-45 hollow points, 12GA with #4-00 buck, or AR with a good load like Hornady TAP in 55-75g, 77g HPBT or perhaps a good 'ol ~63g bonded load.

A .308 or 30-06 hunting rifle, on the other hand, would be an example of way too much power (much of it lost on the perp as the bullets blast through them) and posing an un-needed excess over-penetration concern.

A family member is in danger of a miss through drywall with any sensible self defense load...but a sensible load doesn't pose much (if any ) over-pen. concerns after hitting a perp, nor will they likely leave your home, cross the street, and enter another structure with a miss.

Bartholomew Roberts
March 5, 2011, 10:52 AM
Guns and more, I just now saw this post while updating another post on ballistics.

The problem with the original Box O' Truth tests is the spacing. .223 travels around 3,000 fps. The way it reduces penetration is that when the bullet hits a target, it yaws. As the bullet yaws, the stress on the small bullet is too much and it may break at the cannelure and fragment. The fragments lack a good ballistics coefficient and are small, so they shed energy very rapidly - resulting in a round that poses less of a lethal threat through barriers than most pistol defensive ammo; but providing better terminal ballistics.

The key factor here is whether the round yaws and breaks apart. If it doesn't, it will penetrate. Naturally bullet design plays a large role in that. The problem in the original BOT tests is that the bullet is moving so fast and the barriers spaced so closely together, that the bullet has passed through half the box before the yaw even starts.

Also, using something like a bonded hollow point in a .223 will increase penetration by keeping the bullet together in a single mass.

Strambo summed it up pretty well though - if it meets the FBI criteria, it is going to penetrate multiple interior walls.

Bartholomew Roberts
March 5, 2011, 10:58 AM
O, and on the apples and oranges comment - the problem is pistol loads don't move fast enough to fragment. The ones that do fragment achieve that by pre fragmenting the bullet and using very light loads where the speed can be ramped up. Typically, the result is a round that performs inconsistently and that doesn't meet FBI criteria when it does fragment.

Check out www.brassfetcher.com to see a variety of ammunition tested.

March 5, 2011, 11:15 AM
I like Massad Ayoob's comment on this whole debate. Paraphrased something like "Have you ever seen somebody put their fist through a wall? Ever seen them put a fist through a person? If it can go through a person, it'll damn sure penetrate through drywall."

I don't think there's any point in trying to avoid liability or play it safe by stressing out about which ammo fragments more or has less energy. Even fragments will pass through a wall if they hit it right. Try to keep your lane of fire in a decently safe direction, and hope for the best.

My $0.02.

March 5, 2011, 11:52 AM
I am actually lucky in this case. My house it 110 years old and and the exterior wall is solid brick. Interior walls are three quarters of an inch plaster over wood lathing. Lastly all of my neighbors homes are either solid brick or stone.

So if in the event I do have to defend our home, I would have to miss my target, hit one of our windows, hit one of their windows, and there would have to be someone in line of sight through all of that to put one of my neighbors in danger. Not impossible, but highly unlikely. I am of course assuming that nothing I own would penetrate 18 to 24 inches of brick or stone. Am I wrong?


Owen Sparks
March 5, 2011, 12:14 PM
Let's be realistic. Anything capable of penitrating deep enough into a human body to be a reliable fight stopper will readily pass through two layers of dry wall. Sheet rock is not very tough. You can literally punch your fist through it.

March 5, 2011, 12:24 PM
I wonder if anyone's done drywall tests with low recoil tactical/police buckshot, or with Corbon DPX in handgun calibers?

Owen Sparks
March 5, 2011, 06:15 PM
Living human bone is three times as strong as oak. For a bullet to have enough momentum to make it through skin, fat, muscle, the rib cage or sternum and still penitrate deeply into the vitals, it has more than enough energy to puncture through two layers of dry wall. There is no effective bullet that is totaly safe for indoor use.

The best option that I have found is to fire from a low crouched position behind cover. If you miss the bullet will be traveling at an upward angle and should pass over people sleeping in beds in adjacent bedrooms.

Shadow 7D
March 5, 2011, 06:23 PM
I like the conclusion at the end of the BoT test

If it meets the FBI standard, in other words, it will penetrate a human, it will penetrate through the average home.

Shadow 7D
March 5, 2011, 06:24 PM
Oh, and for those who want to use bird shot, um they did that too....
And came out with if won't penetrate a wall, it won't penetrate a human adequately.

March 5, 2011, 06:45 PM
I have a document (which unfortunately doesn't list the source) which tests various ammo penetration in both drywall walls and gelatin. The fancy 223 fragmenting loads did fairly well, but their gelatin penetration was poor. 00 Buck was just as good as the 55gr tactical 223 load, but penetrates 20" in gelatin. Note that all loads penetrated at least 4 2x4 walls with the first wall being like an exterior sheathed wall w/siding and the others being 2x4 with rock on both sides until the 4th where it was rock-work-sheathing-siding again.

Only the 00 buck and 223 TAP stopped in that 4th wall.

Word document attached with pictures removed (too big). Most important chart attached separately.

Shawn Dodson
March 6, 2011, 08:42 AM
I haven't read all the replies and I apologize for repeating it if someone else has already mentioned it...

A .223 bullet that strikes drywall sideways possesses a much LOWER sectional density than a .223 bullet that strikes point first. LOWER sectional density results in decreased penetration potential because the mass of the bullet is distributed over the profile of the bullet instead of its diameter. (Imagine two rods that each weigh 1 pound. One rod is 1/4" in diameter the other is 2" in diameter. If you were to drop each rod from a height of 3 ft onto a block of pottery clay the 1/4" dia. rod will penetrate deeper into the clay than the 2" rod. The 1/4" rod possesses greater sectional density - its 1 lb. mass is distributed over 0.049 square inches whereas the 1 lb. mass of the 2" rod is distributed over 3.14 square inches.)

Likewise a sideways .223 bullet presents greater frontal surface area than one penetrating point first. The increased surface produces greater resistance to penetration.

Owen Sparks
March 6, 2011, 12:05 PM
No bullet leaves the barrel sideways. It has to hit something first. I'm not sure about the statistics for civilian HD but most shots fired by the police in the line of duty are misses.

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