Frequent question I get asked, and one that I’ve tried to address before, is this:
“If a person’s chest is only 10″ thick, then why should a bullet have to travel at least 12″ and up to 18″? Wouldn’t that just mean massive overpenetration?”
Seeing as I just had to answer that question again, I thought I would put the response here, so that it can be available as a reference for anyone interested.
The question is a simple one, and it has a “common sense” answer: anyone with “common sense” would see, obviously, that since the average person is only 10″ thick, and the vital organs are located in the middle, then obviously you’d only need a bullet that penetrates six or eight inches at most, right?
The problem with this logic, as with all the recent labeling of proposals as “common sense”, is that it’s based on faulty assumptions. As with an example that I’ve used before, it’s just “common sense” to know that the sun revolves around the Earth, right? People could see with their own eyes that the sun rises up, and then sets down, and revolves around the Earth, and the ancient church held it as heresy to say otherwise. It’s “common sense!” Except for the fact that it was wrong.
So in that context, we have to first dismiss the faulty assumption — and that faulty assumption is, that bullet penetration figures = body penetration. They don’t. A bullet that penetrates 12″ of ballistic gel will very likely not penetrate 12″ of a body. Remember, ballistic gel is not a body simulant, it’s a soft tissue simulant, and bodies are made up of many more types of tissue than just soft tissue. Some is firmer than others, and there’s of course those pesky bones too — bones won’t necessarily stop bullets, but they will slow them down more than soft tissue would.
So when we discuss bullet penetration, we have to divorce ourselves from the notion that the bullet under discussion will penetrate a body to the same degree that it penetrates ballistic gel. They’re not the same, nor were they ever intended to be the same. Now, if you’re asking about a bullet fired into muscle tissue (such as a big meaty thigh) then yes, the penetration through muscle will be very nearly the same as the penetration through ballistic gel. And, our bodies are pretty much entirely sheathed in muscle and it’s a fairly safe bet that any bullet impact is going to go through muscle, but even so, that’s not the whole story. Suffice it to say that the penetration figures do not relate to body penetration, so you shouldn’t directly compare them.
Quit Blathering And Answer The Question!
Okay, with that disclaimer noted and out of the way, let’s go on to the question at hand — and, first, the question is: how deep in the body are the vital organs? Unfortunately, there’s not a direct one-size-fits-all answer to that, because (especially among Americans) one size most definitely doesn’t fit all! It depends on what we consider “average” for a human. Skinny small people, obese people, and very muscular people, are all going to have varying depths to the vitals. In general, the average torso is somewhere between 10″ and 12″ thick. The vital organs are located generally within the ribcage, and depending on which organ we’re talking about, it could be as close as 6″ for a straight-on, unobstructed shot (meaning, the target is lined up face-on like a silhouette target, and there’s no arms or other intervening obstacles to get in the way).
Right — so now that’s sorted, let’s again raise the question — if the vitals are only 6″ deep, why on Earth would you need a bullet to penetrate 12″? And if the average person is only 10″ to 12″ thick, wouldn’t a 16″ or 18″ bullet totally overpenetrate right through them?
Again, stick with me and you’ll see that it all does make sense. These are reasonable questions on the surface, but once you start adding it up you’ll see that in fact the actual situation is more complex. First, you don’t want the bullet to reach the vital organs, you want it to disrupt or destroy the vital organs, and that means it has to penetrate deep enough and still have enough speed that it’ll be able to damage the vitals and not just come to a stop right in front of them. So yes, the shallower vitals may be located only six inches deep, but that means you’d want your bullet to go at least 8″, so it has a chance to punch into the organ and disrupt it.
So an 8″ Bullet is All I Need?
No, that’s not what I said. We’re just getting started! Let’s do a little simple math — 6″ of penetration to reach the vitals, plus we want at least a couple of inches of damage travel so that the bullet will sink in and disrupt them, so that brings us to 8″, yes. But we have to factor in that we will almost certainly need the bullet to bust through the ribcage since pretty much all the vital organs are located inside the ribcage (except for the brain stem, obviously), and from a prior study I’ve shown that it takes about 2″ off of a bullet’s penetration capability to get through bone, so add another couple of inches of penetration energy necessary to get through the ribs, and that brings you to needing an absolute minimum of 10″.
Okay, So — A 10″ Bullet Is Good Enough, Right?
Only in the most optimistic possible case — if it’s a straight-on shot — no intermediary obstacles such as arms; no odd angles. Just you and the attacker, squaring up against each other like some Old West duel, each of you standing square on to the other, exposing your chest completely. Does that sound reasonable? Doesn’t sound reasonable to me! If you get in a gunfight, are you just going to stand there and take it? Probably not — and if you’re not going to, why would you expect your attacker to? Hint — he won’t.
So now we have to talk about less-than-perfect situations. If you have to take a shot from a different angle (such as that the bad guy’s knocked you down, so now you’re having to shoot upwards at someone standing over you) then maybe add another 2″ to 4″ of penetration depth necessary because now you’ll be firing through a longer path to get to the vitals. And now, let’s add in an arm, because if the bad guy’s pointing a gun at you, the geometry of the situation pretty much dictates that his arm will absolutely be in the path between your gun and his vitals. Getting through that arm may soak up 5″ of distance, plus another 2″ of penetration power necessary to get through the arm bone.
Okay, But … Um … Oh, I see…
Yep. That’s why the recommendation from the wound ballistics conferences were that for a bullet to reach the vitals, it would require at LEAST 12″ of penetration power through soft tissue, and preferably up to 18″ if you want the bullet to be able to perform in all conceivable shooting scenarios and from all angles (which is perhaps more of a priority for law enforcement, but isn’t strictly limited to law enforcement).
Remember, you won’t be able to choose your shooting scenario. You can’t stop in the middle of a gunfight and say “Excuse me, Mr. Bad Guy, but — see, I’m not a cop, I’m not the FBI, so I didn’t buy that 12″-penetrating bullet. I just thought I’d only need an 8″ bullet. So, could you please stop moving and put your arms up so that I can get a clean unobstructed shot at your chest?”
Um, yeah, good luck with that. I think a better plan is to just follow the advice of the experts who do this for a living, and shop for ammunition that reaches the performance parameters that they identified as necessary: a minimum of 12″ of penetration power through soft tissue, with a maximum of 18″ of penetration. And make sure that the bullet will deliver that kind of performance from YOUR gun! Don’t go viewing tests that were performed from a 5″-barrel pistol, and think that you’ll get the same performance from a 3″ barrel, because you almost certainly won’t. Use ammo that performs to the standards from your gun. After that, it’s just a matter of placing the shot where it counts — or, preferably, be somewhere else before the bullets start flying.
I had an “oh, duh” moment while watching your g2 part 2 video today. At about the 5 minute mark, looking at the plywood shot results, you can see the calibration bb, it’s just shy of 4″, while the trocars that broke off were 5″-6″. I know from experience that a bb at 590fps is going to bounce off skin. Looking at that, it suddenly snapped into focus. Before that I was having a hard time understanding why you said the trocars would probably only leave a flesh wound, but knowing what a bb does to a person gives an easy to compare reference point.
Hi freezercharlie,
You make an excellent point, and one that I should probably clarify for viewers & readers. You’re exactly right. A steel BB weighs about 5.3 grains, and penetrates to 3.5″. The trocars weigh about 6 grains, and penetrate about 4″, so they’re in the same general ballpark.
I’ve tried to explain that penetration in gel isn’t the same as penetration in a body, but unless folks are really “into it”, it doesn’t necessarily make sense to them. A BB penetrates 3.5″ in gel, but as you said, it’s unlikely to even break skin. Now, the G2 R.I.P.’s trocars aren’t going to bounce off skin, of course; they have the advantage of a 48-grain base behind them driving them, but as soon as they hit meat they’re going to expand and break off, and how far are they going to go? Looks like not very, if the flesh simulant is any guide.
That’s why my prediction is for a nasty, ugly, bloody mess of a surface wound, a flesh wound that will leave a terrible scar, and one that you wouldn’t want to experience. But that’s not in the same league as terminal performance or incapacitating performance.
I guess the only way to know for absolutely sure is for some trauma surgeon or coroner to do the first report on an R.I.P. shooting victim, and let us know what really happened. Until then, all we can do is go off of the decades of experience of the IWBA membership and the Wound Ballistics Conferences attendees who all agreed, a heavy/slower bullet offers a better chance of an incapacitating hit than a light/fast bullet does.
I know plenty of obese felons who are at least 18″ thick at the chest. Nor can you count on the Perp to obligingly square his shoulders to you as you prepare to fire.
You are much more likely to be faced with a quartering or transverse shot. Or you might have been knocked to the ground, which not only magnifies the peril of your predicament, it also increases the inches of bone and tissue your upward-aimed shot will have to penetrate to reach the Perp’s boiler room.
The first round fired by the FBI at the infamous 1986 Miami Shootout probably would have ended the fight outright, saving the lives of two agents, and three other agents from injuries that crippled them for life, if it had penetrated 16-17″.
But it only penetrated 14-15″ (including passing through Perp #1’s upper arm). Because it stopped 1″ short of his heart, he was able to fight on for another couple of minutes, despite receiving a further 10 gunshot wounds. Even the 12th and final wounding, a .38+P to the head administered at coup de grâce range, failed to kill him. The proximal cause of death was the very first gunshot wound he received, before any FBI agents had been seriously wounded, and which transected his brachial artery, allowing 1.3 liters of blood to escape and spill into his chest cavity. In the end, the FBI’s very first shot had killed him, it just took too long in the doing.
In 1987, in response to the Miami shootout, the FBI convened its own Wound Ballistics Workshop. The single most important take-away from their work can be condensed to one short sentence: “Too little penetration will get you killed.”
In a similar vein, if you are unfamiliar with his work, you owe it to yourself to look up Dr. Gary K Roberts (DDS) on the Interwebs. His forum screen name is DocGKR. He’s a “gun guy” and a Lt Cdr in the USNR. He has leveraged his status as a medical professional and a commissioned officer in the US armed forces to gain access to a broad spectrum of civilian & military GSW reports, which he studies to evaluate bullet effectiveness.
Once a particular handgun load has passed the FBI’s eight protocol duty ammunition tests, he monitors official accounts of its real world performance. In the guise of DocGKR, he maintains a list at several different military and LEO web sites of the commercial loads that have received FBI approval AND continue to perform suitably in the field.
IMHO, there is no one else on the Interwebs who communes with us common schlubs, and who has such comprehensive real-world handgun cartridge effectiveness information as Doc Roberts. Props to the folks in the Blogosphere and on YouTube who do penetration testing AND are rigidly adhering to the latest standardized testing procedures, but if it ain’t on DocGKR’s list, I AM NOT entrusting my family’s safety to it.
Hi Bruce,
I’m very familiar with Doctor Roberts’ work, and we communicate at times; he has complimented my work on the .380 Ammo Quest, for example. I follow DocGKR’s work, and we study the same works and follow the same protocol. Where we differ is that DocGKR is primarily testing for law enforcement agencies and thus is testing to strict FBI protocol including barriers, and primarily tests from service caliber guns with 4″+ barrels. Whereas I am not concerned with law enforcement usage, I’m interested in concealed-carry, self-defense uses, and therefore I test from common self-defense concealed-carry pistol barrels. When using organic gel I use the exact same materials and standards of evaluation as DocGKR regarding the bare gel and denim tests, but I don’t run the additional tests he does, of penetration through auto windshields, plywood, drywall, and car door steel. Those are primarily (if not exclusively) the domain of law enforcement and simply not necessary for personal defense. Instead, I follow the IWBA protocol of two tests, bare gel and denim-covered, but still held to the same penetration and expansion standards.
Gary Roberts’ ammo list is the result of extensive testing, and it’s a great list, BUT — it’s only really applicable to you IF you’re using a pistol of comparable barrel length. If you’re using a 2.75″ barrel, you cannot count on getting the same performance as DocGKR got from a 5″ barrel, for example. One of the reasons I got into ammo testing is because DocGKR said, in regards to barrel length, “Once you get below 3.5″, you’re in uncharted territory.” So it was my goal to go chart that territory. I think it’d be fair to say that there’s a huge percentage of people carrying pistols for self defense, who are carrying barrels of less than 4″ in length; basically any pocket .380, or pocket 9mm, will fall in that category. People in this arena need and deserve comprehensive testing just as much as the LEOs do, and that’s the questions I’m attempting to answer in my testing.
If you’re using a pistol with a barrel of 4″ – 5″, then yes, DocGKR’s list is a superb place to go for recommendations — and it’s where I’d go too. But if your barrel length is shorter than that, then you shouldn’t take his list as appropriate for your pistol. Barrel length matters, a lot, and an inch or two can make a big difference in how the ammo performs. Bullets are designed to properly perform at a certain velocity, and if you vary too much from that velocity, you can get substantially different results.
I support, endorse, and believe in the work DocGKR is doing. I just find that he’s not testing from the barrel lengths that are of interest to me, and (by extension) all the other people who are carrying subcompact pistols, and therefore there’s work yet to be done.
Agreed 100% I’ve took issue with some of your logic on other subjects but you are right on the money here, great write up, an excellent job. Thanks.
I want to thank you for ALL of your ammo reviews. I was one of the people that bought into the hype of the RIP round. Thanks to your channel I now carry hst in 45 as well as 9mm. I have done my own tests also and love the performance of the round. I was wondering if you plan on doing test for more short bbl 45? I have the xds 3.3 and would love to see more in that platform. Again.. thank you for your honest no holds barred FACTS. KEEP UP THE GREAT WORK. – Ray-
Yes, sometime later this year I’ll start the .45 testing, from an XD-S and from a Glock 30SF. Thanks for the kind words!
So does ballistics gel actually simulate soft tissue or is it just an arbitrary comparative medium? I’ve read other articles that make it sound like the gel is just a way to compare shots side by side, but that the properties of the gel itself don’t actually mimic anything in the human body. If that’s the case, then how is testing in ballistics gel any better than using precisely calibrated Play-Doh or identical giant gummy bears?
If I read your article right, though, it sounds like the gel (if properly mixed) actually does simulate the material properties of tissue found in the human body. In other words, if we took just some soft tissue (no bones or firm stuff) out of my body right now and made it into a block, and fired identical ammunition into it and into a ballistics gel block, the penetration and expansion should be roughly the same in both blocks. So proper ballistics gel is NOT just an arbitrary medium. Did I get that right?