Ammunition Drywall Penetration Analysis Test (Adpat)

[Frontpage]

As part of ongoing efforts to explore the surprisingly fertile intersection between the fields of "scientific inquiry" and "shooting things", I decided to see what happens when .223 ammunition designed for expansion is fired into interior walls.

Inspiration came from the Box 'o Truth website where the author compared penetration of various rounds through simulated walls. Surprisingly, the least penetrative centerfire round turned out to be 55-grain .223--fully jacketed, no less. In some cases, these bullets passed through fewer walls than the canonical home-defense load of 00 Buckshot, thereby simultaneously blowing holes in both drywall and conventional wisdom.


In retrospect, it's not too surprising. Fast bullets are good at penetrating relatively thin rigid surfaces, such as metal, because they punch clean through before the metal has a chance to deform. But when passing through solid objects, speed becomes something of a liability. Viscous drag exerts a slowing force on an object proportional to its surface area times the square of its velocity, but that force translates into a reduction in speed in a manner directly proportional to the object's mass. These two factors combine mean that light and fast projectiles dump velocity much more readily than slow, heavy slugs.


Because surface area and coefficient of friction are factors in a bullet's propensity to slow down when passing through things, it made me wonder: What would happen to expanding .223 bullets if they hit drywall? Theoretically, expanding should increase surface area and therefore reduce penetration even further. But would it actually make enough of a difference to notice?


Referring to the Venn diagram above suggests that answering these questions will require hearing protection.

[Targets]

In the interests of ensuring domestic harmony and minimizing police involvment, simulated walls were used instead of the interior of my house. I built several wall sections simulating the space between studs to test the worst-case scenario of a straight-on wall shot that misses the heavier supporting 2x4s. Building standards call for studs to be separated by 16 inches center-to-center, but these sections are 16 inches outside-to-outside to help them hold together. Hopefully this is close enough to the real thing to realistically simulate the stiffness of inter-stud drywall. 5/8 inch drywall was used in order to comply with all relevant building codes.

The truck was removed before shooting.

The first wall was placed five feet from the firing line and subsequent walls were spaced ten feet apart, which should roughly simulate indoor distances. Separation between the walls is important if rounds flatten out or break up, since this gives air resistance a chance to work against suddenly non-aerodynamic shapes. Spacing the walls so close together and shooting straight on provides a realistic yet worst-case scenario for interior wall penetration.



[Guns]

A gun shot.

Rifle ammo was fired from a Mini-14 Tactical, whose 16.25-inch 1:9 twist barrel should produce ballistics representative of most common .223 semi-automatic carbines.


The shotgun used was the canonical Remington 870, specifically a Marine Magnum featuring an 18 inch barrel with a cylinder choke.


Speaking of canonical, a 1911 provided the platform for .45 ACP. It's a custom build belonging to, and built by, the photographer.


9mm ammo was put through an FM Detective, a Hi-Power variant with a shortened slide. Its barrel is about 3.6 inches long, which makes it comparable to most concealed-carry-oriented 9mm handguns. As it turned out, barrel length with handguns probably wouldn't make much difference.

Sig nificant part of the testing.

Finally, a Sig P230 provided the platform for testing .380 ACP.

[Frontpage]

Ammunition



Most of the ammunition tested consisted of various flavors of .223 designed to expand on impact, but as long as chunks of lead were being chucked through simulated walls, it made sense to include some typical handgun and shotgun rounds. These would act as a control group for the rifle rounds, and maybe also put to rest persistent myths about handgun and shotgun penetration compared to rifle rounds.



[Hornady TAP]

TAP ammo is one of the most popular self-defense and police ammunitions. It has always held personal appeal because Hornady publishes gel test results on their website and identifies the intended purpose of the cartridge (e.g. reduced-penetration or barrier breaching).


Hornady's website shows noticeably different terminal behavior in gel for their 55 and 60 grain TAP ammunition, so it makes sense to test both on drywall. These two bullet weights both use ballistic tips like the A-Max design. A-Max bullets are designed for accuracy; like traditional match hollowpoints, the base is encapsulated in copper. But instead of drawing the jacket all the way forward and leaving a tiny dimple, A-Max bullets use a pointed plastic plug. The plastic tip reduces drag and, as a nice bonus, supposedly encourages bullet fragmentation on impact.


After posting this article, one reader pointed out that Hornady does not sell 55- or 60-grain A-Max bullets, although they do sell V-Max bullets in those weights. Thus, it's more likely that TAP ammo is topped by V-Max bullets than A-Max--but it's impossible to say for sure.

I couldn't source any of the Hornady TAP that uses their 40-grain V-Max bullets, but found cartridges from Fiocchi using the same bullet that should serve as a reasonable stand-in. V-Max bullets are almost identical to A-Max bullets, but are lighter and have a much thinner jacket. The "V" in "V-Max" stands for "varmint", the intended target for these bullets. Their thin jacket, light weight, and high velocity encourage fragmentation sufficiently explosive to reduce woodchucks and prairie dogs to fine pink mist. Whether the ability to disintegrate hapless rodentia will translate into reduced wallboard penetration remains to be seen.



[Winchester Ranger JSP]

Another approach to encouraging bullet fragmentation is just leaving the tip as bare lead. This school of thought will be represented by some Winchester Ranger soft-point ammunition. Like the TAP cartridges, two weights of projectiles will be used; this will provide an apples-to-apples comparison of performance at the same bullet weight.



[7.62x39mm FMJ]

Given the wide variety of .223 rounds, it seemed only fair to include another intermediate rifle cartridge. Commercial FMJ 7.62x39mm isn't an optimal defensive round, so this isn't so much a serious test but instead a desire not to miss the chance to shoot a common cartridge through drywall to see if it did anything interesting.



[.45 ACP Ball]

Do all walls fall to hardball? American Eagle ball ammo represents the canonical 230-grain .45 ACP load, and should be equivalent to any of the dozens of ball ammo loadings commonly available.



[9mm JHP]

Another popular loading for self-defense firearms is 9mm jacketed hollowpoints. 115 grain is the lightest common bullet weight in 9mm, so it made sense to use some of those to represent the light, fast, and hollowpoint end of the handgun round spectrum.



[.380 Auto Ball]

.380 Auto is enjoying a surge in popularity as manufacturers introduce more guns for it. Many people eschew hollowpoints in these small guns, both on the grounds of terminal ballistics (hollowpoints in .380 tend to underpenetrate) and for increased feeding reliability. When it was introduced, it was considered a powerful chambering for a defensive arm; nowadays, most people consider it below their acceptable minimum power level. Would walls feel the same way?



[12-gauge 00 Buckshot]

Any selection of defensive rounds would be most remiss without the inclusion of some good old-fashioned 00 Buck. The particular variety used here was Winchester "military-grade" buckshot. Guess that means it was made by the lowest bidder. Even restricting the field to 00 buck (which leaves out the increasingly popular #1 buckshot loading), there's an amazing variety of loads available. The Winchester ammo should suffice to give a general idea of how many walls buckshot will go through.



[Summary]

[Summary]

[Frontpage]

Testing

[Fiocchi 40-grain VMax]

Due to the limited number of wall sections available, it made sense to start with the round that seemed likely to penetrate the least number of walls: The zippy, light, and thin-jacketed V-Max ammo.

The hypothesis turned out to be correct: V-Max bullets started fragmenting within the first sheet of drywall and completely blew to pieces on their way out of the second sheet, leaving dramatic craters.

Most of the rounds had fragmented by the time they reached the second wall. A couple roughly circular holes suggest that some of the rounds were more intact than others when they hit the second wall. My bet is that these rounds didn't fragment as much in the first wall because they were shot so close to preceding rounds that they passed through the craters in the rear of the wall.

These were probably the rounds responsible for reaching the third wall, where they left small holes.

It's debatable whether rounds using V-Max projectiles are the ideal choice for defensive purposes, as ballistic gelatine tests show such bullets penetrating far less than the FBI's recommended minimum of twelve inches. However, this lack of penetration in gel works in their favor when dealing with wallboard.



[Handgun Rounds]



Every time there's a debate about the best firearm for home defense, someone inevitably chimes up to say that among his reasons for keeping a handgun for this purpose is the fact that handgun bullets won't go through as many walls as rifle rounds.


As a categorical statement, this is completely incorrect. Here's proof. First, some .45 ACP.

It's said "they all fall to hardball;" apparently this includes walls, because the bullets sailed through all three walls without showing any sign of slowing, tumbling, or deforming.

.45 ACP FMJ, Wall 1

.45 ACP FMJ, Wall 2

.45 ACP FMJ, Wall 3

Law enforcement in the 1920s discovered that .45 ACP didn't like to go through heavy metal car doors and switched to the high-velocity .38 Super. If the car doors had been made of gypsum, it wouldn't have been an issue. But that raises a question: Will there be any significant difference in penetration between .45 ACP FMJ and 9mm JHP?

9mm jacketed hollowpoints (115-grain Speer Gold Dots, to be precise) didn't fare much better:

9mm Speer Gold Dot, 115 grain, Wall 1

9mm Speer Gold Dot, 115 grain, Wall 2

Misalignment of the shots on my part prevented any rounds from reaching the third wall. Retesting was planned, but abandoned after we saw what the diametrically similar but ballistically inferior .380 rounds did.

The only handgun round that failed to consistently penetrate all three walls was .380 ACP, represented here by Magtech FMJ. All three rounds went through the first wall.

.380 FMJ, Wall 1

One round hit the dirt before the second wall, but the other two went through.

.380 FMJ, Wall 2

Only one round failed to have a close encounter of the ground type before reaching the third wall, but that one penetrated the first sheet of drywall and bounced off the back of the second.

.380 FMJ, Wall 3

It's safe to say that there are better choices than handguns if wall penetration is a concern.



[Wolf 7.62x39mm FMJ]



In case you were wondering about those intriguing keyholes in some of the handgun photos, those come from one of the more surprising tests: Wolf 7.62x39mm 122-grain FMJ bullets fired from an AK.

7.62x39mm is not known for its fragmentation, especially in full metal jacket form, so it was expected that these rounds would punch neat holes through all three walls.


This was true for the first two walls:

7.62x39mm, Wall 1

7.62x39mm, Wall 2

Between the second and third wall, the bullets must have slowed enough to lose stabilization, because every round that managed to hit the wall was tumbling when it did. They still went through all the walls, but at least they made nifty-looking holes in the process.

7.62x39mm, Wall 3

[Winchester Ranger 55-grain Softpoint]

Because we'd been punching clean holes through the boards, it seemed logical to make the most of the relatively clean second wall by choosing a round from which we didn't expect a great deal of expansion: Winchester Ranger 55-grain softpoints. I'm not sure why we thought these rounds would hold together through all the walls, because it sure seems like a silly assumption given what happened.


The first rounds provided the ubiquitous clean holes through the first wall.

Winchester Ranger 55-grain Softpoints, Wall 1

But only chunks hit the second wall. These were larger fragments than the V-Max bullet produced, and several of them penetrated the second wall, continuing on to the third.

Winchester Ranger 55-grain Softpoints, Wall 2
Preexisting holes digitally removed; click here for original.

Only one fragment appeared to make it through the first of the drywall sheets in the final wall; the rest just left tiny speckles.

Winchester Ranger 55-grain Softpoints, Wall 3

[Hornady TAP 55-grain]



Given that the first two .223 rounds had blown to pieces in the first section of simulated wall, we had similar expectations for the TAP fitted with the 55-grain A-Max bullet.

Hornady TAP 55-grain, Wall 1

Hornady TAP 55-grain, Wall 2

Hornady TAP 55-grain, Wall 3

Haha, surprise! A-Max is designed for accuracy, not terminal effect. Although Hornady's website shows impressive fragmentation in ballistic gel, this same behavior was notably absent from the bullets in drywall. All three rounds tested drilled neat holes through every single wall. The polymer tip is clearly intended to aid external ballistics more than terminal ballistics.



[Hornady 60-grain TAP]



The effect of 55-grain TAP was so contrary to expectation that it demanded immediate investigation of how the slightly heftier 60-grain equivalent performed. The results here were, if anything, even more surprising.


As usual, the entry holes were neat and tidy.

But the second wall showed exactly two holes per bullet, with very consistent spacing between the holes from shot to shot. The bullets fragmented into two pieces in a very repeatable manner, perhaps snapping at the cannelure.

By the third wall, consistency in spacing, size, and penetration had vanished. This is to be expected if dealing with tumbling, irregular chunks of bullet that have had multiple sheets of drywall to throw off their surprisingly predictable fragmentation pattern. However, the fragments that struck this wall appear to cluster into locations rougly corresponding to the spacing observed in the other two walls.

Finishing off the .223 ammo selection was a return to Winchester Ranger softpoints, this time with a heavier bullet.


The first wall showed yet another set of identical entry holes.

The second wall showed impacts similar to what was seen with the lighter Rangers, but with less consistency in size. In addition to the tiny spatters from small fragments, several fragments were large enough to punch through at least the first sheet of drywall.

Preexisting holes digitally removed; click here for original.

It didn't look like they made it through the second wall, though, as there were no new marks on the third. The heavier weight and ostensibly different bullet construction ("Power-Point" vs. "Pointed Soft Point") didn't seem to make much difference where the walls were concerned.



[Winchester 12-Gauge 00 Buckshot]



Of course, no internal wall penetration test would be complete without including some good old-fashioned 00 Buck. We saved this one for last on the assumption that it would destroy entire sets of walls. This assumption turned out to be completely correct.


From five feet, the damage wasn't too bad. All the shot pellets clustered into a single hole just large enough to put a finger through.

Not only had the shot spread out quite a bit by the time it reached the second wall, but it didn't slow down much at all. It left a healthy spatter of neat round holes through both sides.

Note dents from shot cups.

This trend continued in--and through--the final wall. If buckshot is supposed to limit penetration through interior walls, it does so only at a theoretical level.

[Summary]
[tbl="border=0 bgcolor=grey align=center"]
[tr][th="bgcolor=orange colspan=5"]Ammunition Drywall Penetration[/th][/tr]
[tr][td]Ammunition[/td][td="bgcolor=#53760D"]Wall 1[/td][td="bgcolor=#3FB058"]Wall 2[/td][td="bgcolor=#808000"]Wall 3[/td][/tr]

[tr][td]Fiocchi 40-grain VMax[/td][td="bgcolor=#53760D"]penetrated[/td][td="bgcolor=#3FB058"]fragments, some penetration[/td][td="bgcolor=#808000"]few speckles, no penetration[/td][/tr]

[tr][td]Federal 230-grain .45 ACP FMJ[/td][td="bgcolor=#53760D"]penetrated[/td][td="bgcolor=#3FB058"]penetrated[/td][td="bgcolor=#808000"]penetrated[/td][/tr]

[tr][td]Speer 115-grain 9mm Gold Dot JHP[/td][td="bgcolor=#53760D"]penetrated[/td][td="bgcolor=#3FB058"]penetrated[/td][td="bgcolor=#808000"]missed (user error)[/td][/tr]

[tr][td]Magtech 90-grain .380 FMJ[/td][td="bgcolor=#53760D"]penetrated[/td][td="bgcolor=#3FB058"]penetrated[/td][td="bgcolor=#808000"]penetrated first wall[/td][/tr]

[tr][td]Wolf 7.62x39mm FMJ[/td][td="bgcolor=#53760D"]penetrated[/td][td="bgcolor=#3FB058"]penetrated[/td][td="bgcolor=#808000"]penetrated (keyholes)[/td][/tr]

[tr][td]Winchester Ranger 55-grain Softpoint[/td][td="bgcolor=#53760D"]penetrated[/td][td="bgcolor=#3FB058"]fragments, some penetration[/td][td="bgcolor=#808000"]speckles, one fragment penetrated first wall[/td][/tr]

[tr][td]Hornady TAP 55-grain[/td][td="bgcolor=#53760D"]penetrated[/td][td="bgcolor=#3FB058"]penetrated[/td][td="bgcolor=#808000"]penetrated[/td][/tr]

[tr][td]Hornady 60-grain TAP[/td][td="bgcolor=#53760D"]penetrated[/td][td="bgcolor=#3FB058"]penetrated, two pieces[/td][td="bgcolor=#808000"]fragments, some penetration[/td][/tr]

[tr][td]Winchester Ranger 64-grain Power-Point[/td][td="bgcolor=#53760D"]penetrated[/td][td="bgcolor=#3FB058"]fragments, no total penetration[/td][td="bgcolor=#808000"]no hits[/td][/tr]

[tr][td]Winchester 12-Gauge 00 Buckshot[/td][td="bgcolor=#53760D"]penetrated[/td][td="bgcolor=#3FB058"]penetrated[/td][td="bgcolor=#808000"]penetrated[/td][/tr]
[/tbl]

[Frontpage]

Conclusions

[Cartridge Conclusions]



The biggest surprise of the entire test was how much differences in bullet construction affected the way .223 rounds behaved when passing through walls. If overpenetration must be minimized over all other concerns, something based around the V-Max bullet would be a good choice; however, both the Winchester and Fiocchi softpoints turned in very similar wall penetration, but published data for the Winchester suggests it does better in gel penetration than the V-Max loads. Given that the softpoint bullets were heavier and therefore more likely to reliably cycle a gas-operated action, some kind of softpoint would seem the ideal balance between terminal ballistics and minimizing overpenetration.


Bullet construction made a difference in penetration, but there was no significant difference in behavior between the two brands of softpoints tested beyond the fact that the Winchester's fragmentation was more consistent. This could just be a coincidence, though, so it would be educational to track down more varieties of softpoint ammo and see if the observed trend continues.


The amount of unsuspected and surprising behavior we saw with various rifle rounds left us eager to try out more types of ammunition just to see what unusual and surprising results will ensue. I'd love to see what happens with some Hornady TAP 110-grain .308 rounds, or perhaps some of the Wolf Military Classic 7.62x39mm rounds that are said to perform well in ballistic gel. What about the 5.45x39mm rounds currently available as surplus? Or FN's 5.7x28mm round? Truly, blowing gigantic holes in drywall with consequent awesome explosions of gypsum dust demands further study. For purely scientific purposes.


Moving away from rifle rounds takes us from fascinating discoveries into the realm of mythbusting. Handgun rounds, for instance, may penetrate less than rifle rounds--but only if the rifle rounds in question are full-power ball ammo. The relatively slow speed and heavy weight of handgun bullets make them a poor choice for limiting interior wall penetration, which is why professional door-kicker types have abandoned pistol-caliber submachineguns in favor of .223 carbines.


Shotguns may be the most powerful repeating shoulder-fired gun available, but when stoked with 00 buckshot they are certainly not a low-penetration option. In fact, the way the pellets spread out after passing through intermediate barriers makes the safety of anyone or anything within three rooms of a shotgun blast highly dubious.



[Testing Conclusions]



The most notable thing learned from all these tests has nothing to do with cartridges at all, but with testing methodology. The tests were run in a somewhat ad-hoc manner due to the fact that other people selfishly insisted on using the range at the same time, so it was not always possible to call a cease fire every three shots. This forced us to do shooting and photography by batches, which led to come confusion when sorting through the photos afterward.


Confusion was also caused by the amount of sharing the limited quantities of drywall necessitated. It can be tricky to precisely characterize the fragmentation behavior of a round when a section of wall is already covered in the spattered remnants of another bullet. The subtly different behavior seen in different softpoints suffered the most from this.


Because the test results were so surprising and interesting, it's clear that another round of drywall testing is required, but this time with improved test mechanisms based on lessons learned from the initial test.


For starters, it would be handy to have a way to pull all the wall sections back over the line without calling the range cold. This would allow photographing the holes for each shot without irritating the other shooters at the range or requiring an inordinate amount of time for the entire test. Adding the ability to clamp and remove wall sections from the studs could allow photographing both the entrance and exit holes (even inside the wall sections), thereby providing a more detailed view of how and where fragmentation or tumbling occur.


Finally, there are a lot of cartridges out there just begging to be blasted through drywall to reveal their no-doubt fascinating behavior. 5.7x28mm comes to mind, as does 5.45x39. What about #1 buckshot, or reduced-recoil 00 buck, or softpoint bullets in other calibers, like 7.62x39 or even .308?


With so many questions left unanswered and so many walls yet unshot, it seems clear that there is another article yet unwritten.

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[bunnielab]

Tfr brought up mosins faster then I thought they would.

What would it take to get you two some gel or a chrono that you dont care about too much?

I realy believe that way too much is made of drywall penatration it's self and not the actual question we are asking, namely "What will a bullet do to a person after it has gone through 2 layers of sheetrock?"

The results you got from the .223 rounds is especialy intresting as it looks like some of those fragemnts are super tiny and I would love to know how much energy they actually have left. Skin is really resiliant stuff and from years of informal "testing" I know that most any bb gun will shoot through one layer of drywall but most cant even break the skin. I would be willing to pitch in for the pruchase of some gel to see what effects these .223 fragement have on it.

[Miso Beno]

Tfr brought up mosins faster then I thought they would.

What would it take to get you two some gel or a chrono that you dont care about too much?

I realy believe that way too much is made of drywall penatration it's self and not the actual question we are asking, namely "What will a bullet do to a person after it has gone through 2 layers of sheetrock?"

The results you got from the .223 rounds is especialy intresting as it looks like some of those fragemnts are super tiny and I would love to know how much energy they actually have left. Skin is really resiliant stuff and from years of informal "testing" I know that most any bb gun will shoot through one layer of drywall but most cant even break the skin. I would be willing to pitch in for the pruchase of some gel to see what effects these .223 fragement have on it.

The problem with gelatin is trying to gain access to a freezer of sufficient size and then transporting it to the location of the shoot.

[lee1000]

Great write up!!! I'm surprised I didn't find this when doing a google search. Will you be testing any Hornady 223 TAP FPD?

http://www.hornady.com/store/searcha...%5D=&x=13&y=14

Someone on The High Road directed me here. I asked a question that you pretty much already had an answer to.

http://www.thehighroad.org/showthread.php?t=495942

Thanks for putting this info out there!!!!

[Fang]

Great write up!!! I'm surprised I didn't find this when doing a google search. Will you be testing any Hornady 223 TAP FPD?

http://www.hornady.com/store/searcha...%5D=&x=13&y=14

Someone on The High Road directed me here. I asked a question that you pretty much already had an answer to.

http://www.thehighroad.org/showthread.php?t=495942

Thanks for putting this info out there!!!!

Interesting; I didn't know Hornady had a civilian-market version of these rounds. Looks like we've got plenty of materials for the next set of tests. It'll be interesting to see if any of these TAP rounds beats the softpoints for minimizing penetration.

Edit: Took a more extensive look at the link you provided and man is that a lot of options. Gonna have to save my pennies for this one.

[lee1000]

Interesting; I didn't know Hornady had a civilian-market version of these rounds. Looks like we've got plenty of materials for the next set of tests. It'll be interesting to see if any of these TAP rounds beats the softpoints for minimizing penetration.

Edit: Took a more extensive look at the link you provided and man is that a lot of options. Gonna have to save my pennies for this one.

Thats great, when do you think you will get around to it? I shot some TAP FPD 55 grain out of my LWRC 1:7 and it grouped well.

So where are you out of?

[Miso Beno]

Thats great, when do you think you will get around to it? I shot some TAP FPD 55 grain out of my LWRC 1:7 and it grouped well.

So where are you out of?

Fang and I are both out of Washington state within 40 miles of Seattle, and I believe we were looking at having a drywall redux in the spring. Weather permitting, of course.