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Penetration Question

Discussion in 'Handguns: General Discussion' started by bullseye308, Jun 7, 2018.

  1. BSA1

    BSA1 member

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    Heck! I was there.

    Well sort of. A buddy got a 1911 in 10mm and the original Norma ammunition when it was introduced which we shot side by side with the 45 ACP. The Norma ammo was HOT stuff.

    I also recall a interview with a top FBI Official at the time who said something along the lines of "We shoot a lot of vehicles and are satisfied with it's performance." I thought this was a strange statement since FBI agents are not street cops making a lot of traffic stops.
     
  2. Garandimal

    Garandimal Member

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    Gel - is not human target.

    That said, it takes ~ 12" to reach the heart from a right side hit in the upper arm.

    Clothing->arm/bone/arm->clothing--->clothing->ribs->lung->heart.

    Worst case.




    GR
     
  3. Kano383

    Kano383 Member

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    The reason there is so much debate and hair-splitting when one talks about handgun self-defense ammo is, to start with, that handguns are generally underpowered for the target at hand, i.e. human beings.

    Bring a .44 magnum or bigger into the debate, and you’re a few steps up the ladder - but the cons in terms of firearm choice, weight, controllability, etc. are such that it’s not really a winning proposition.

    So you end up with the “accepted” SD calibers, and having to thread a line with precipitous compromises on both sides.

    Personally, I’m much more concerned about under-penetration than over-penetration. If a bullet stops too early in a body that I want to put out of commission, that’s a problem; whereas if the bullet continues past the vital organs it was supposed to reach, I don’t really care in the heat of the instant.

    The second concern is trajectory. I’d rather have the bullet continue on a straight path than taking unexpected turns and swirls.

    The third is tissue damage. Better to have a torn up wound channel than a narrow puncture wound.

    In rifle bullets, study effected by several gun-nuts in the past decades have shown that non-deformable flat meplat bullets produce the kind of deep, straight penetration with large wound channels that allows you to have basically “one load for all” when hunting dangerous animals (gangbangers fall into this category from a purely technical point of view).

    Nothing new here, Elmer Keith was already a proponent of flat-nosed bullets, but with the advent of on-the spot CNC machining and computer analysis, people have been able to conduct extensive tests, and gain an invaluable understanding of what works. Do a search on Michael McCourry and his work on bullets: that guy has spent a fortune in money and time to design, try and test things that major manufacturers should have explored long ago.

    Some manufacturers have come up with fancier variations on that theme, designing solid bullets that have a large frontal area, and shapes that disrupt soft tissues even more than a mere flat. I have tested some of these in real life, and that’s all I use now in “do-or-die” situations.

    Handgun bullet manufacturers have also introduced bullet designs based on the same principles: solid construction, blunt nose, tissue disruption insured by a particular shape. These do not care much about barriers, do penetrate very well, and do provide better wound channels than round-nose FMJ.

    I have not tested these on live targets, but everything I have read, seen, and tried myself has led me to adopt them as my EDC load of choice, regardless of caliber.

    When I shoot at something bad, I do not want my bullet to stop half-way in because it was designed around a block of ballistic gel that did not have a foot of lard in front of it, and forgot to don his heavy winter rainproof polar coat before the tests.
     
    Last edited: Jun 23, 2018
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  4. MTMilitiaman

    MTMilitiaman Member

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    Penetration is a good thing. That is how these things work.

    The FBI requirement came from the Miami Dade shooting in which agents were killed because a bullet failed to reach the heart on a shot from side presentation. A bullet should be able to reach the vitals from every angle because Murphy is an SOB. There is a good stance an attacker is going to have his arms up between you and his vitals. A load getting 8 to 10 inches of penetration under controlled conditions in a homogeneous substance maybe not be able to get through both sides of a jacket and the forearm bones between, another layer of jacket, the pectoral muscles, and into the chest cavity with enough left to reach larger cardiovascular structures located deeper in the chest. Consider 1/3 of Americans are obese and over 40% are overweight. It is generally better to have too much penetration and watch your backstop than rely on marginal penetration to justify shooting towards an unsafe backstop. Erring on the side of caution means packing something with enough power to reach vitals from any angle under imperfect conditions so you know you can get the job done when Murphy shows up. Not shooting towards something you don't intend to destroy is one of the Four Rules and common sense regardless of what you're shooting.
     
  5. bullseye308

    bullseye308 Member

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    Logs of good info provided by all, thank you all. I have learned a lot once again on this forum, the library of knowledge here is simply amazing. Guess I’ll put some of my newly acquired knowledge to use and re-examine my self defense loads. I’m going to stick with gold dots, but will have to speed them up a bit and re-test for accuracy and see what the recoil recovery is like for dropping multiple rounds on target rapidly.
     
  6. RetiredUSNChief

    RetiredUSNChief Member

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    "Penetration, however slight, shall be sufficient to complete..."

    Oh, wait...wrong subject!

    :D:D

    Don't get too wound up in this. The minimum 12 inches penetration is no more than an FBI standard established after all kinds of studies and tests in which they came to the conclusion that ammunition which could be demonstrated to meet this depth of penetration in ballistic gel would be adequate for their purposes.

    You can argue/analyze any number of instances or circumstances in which the particular standard will or will not suffice, will or will not be "overkill". But then, you can argue these things for ANY handgun ammunition, because none of them are "perfect" for all circumstances and instances.

    Oh, and by the way...it IS a standard for HANDGUN ammunition. Handguns are notoriously underpowered when compared to the capabilities of their rifle cousins. So think of it as a way of saying "Because handguns are very limited in power, this is the minimum standard the FBI has determined to be acceptable for use against human targets."



    EDIT:

    Ballistic gel is also not intended to be representative of the human body, per se. It's a reproducible medium standard which anybody can use in order to make quantitative analysis and comparisons of ammunition performance.

    It is only meant to be a facsimile of swine/human soft tissue, in a homogenous fashion. (Meaning it has uniform density and consistency throughout and does not have various layers of differing densities and consistencies.)

    There is a reproducible standard for making it that anybody can follow, which includes a calibration check method.
     
    Last edited: Jul 7, 2018
  7. JohnKSa

    JohnKSa Moderator Staff Member

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    Correct. However it IS designed to be a medium which, when shot, will provide an analog for human tissue for penetration/ballistic testing purposes.

    In other words, while it obviously does not replicate human tissue in terms of appearance, or density variability, or in any other number of ways, it was specifically designed so that in spite of those differences from human tissue, it DOES act very much like human tissue in terms of projectile penetration and temporary stretch characteristics when shot.

    And, although assertions to the contrary are common, in spite of the fact that it doesn't contain bones or lungs, or other features common to human tissue, the penetration figures obtained from gelatin have been determined to provide good performance in terms of simulating penetration figures in live human tissue. Said another way, it is designed to provide penetration resistance which replicates the average penetration resistance of the human body; including bones and other non-uniform features.

    There's a reason it is ubiquitous--it does what it's supposed to do. There's a reason it hasn't been replaced by something better--the people who came up with the recipe did a good job and there's no need for anything better.
     
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  8. Texas10mm

    Texas10mm Member

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    I've read in several places that skin is equal to 2-4" of gel. If you accept 2" then a shot through an forearm is at a minimum 6-8" of penetration. Then add another 2" to penetrate the skin of the body. You quickly start to see what 12" of gel penetration is the minimum.

    On another firearms forum there is/was a member who was LEO. He posted a video of a gun fight where he was shot in the forearm. It didn't leave him writhing on the ground. It did incapacitate his arm, but didn't prevent him from getting out of the danger area.
     
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  9. JohnKSa

    JohnKSa Moderator Staff Member

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    I've read similar things, however I believe the statement applies primarily to unshored exits. That is, if nothing is pinning the skin tightly in place, and it can stretch, the bullet will, in stretching and breaking through the skin as it exits, expend about the same amount of energy as it would take to penetrate about 2" of gel. This is why it is not uncommon to find a bullet just under the skin on the off-side of an animal.

    I have also had difficulty nailing down whether this equivalent penetration figure applies primarily to animals, primarily to humans, or across the board. I would think the latter is unlikely as some animal skin is considerably tougher than human skin.

    However, the point is well taken. Exiting the skin, and then having to penetrate the skin/clothing again, especially already expanded, places additional demands on the bullet that need to be taken into account during bullet design.
     
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  10. 481

    481 Member

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    Not everyone can handle the caliber. Some can, some cannot. Just how it is. I believe that most of us would rather see a law enforcement officer equipped with a caliber that they can control and make hits with, rather than with a caliber that they cannot control and may miss with leading to the injury/death of a bystander downrange. Like it or not, not every law enforcement agent is a barrel-chested ''he-man'' capable of bench-pressing 300+ pounds. ;)

    Such a shot (as described above) is highly unlikely and not the point that is being made in such comparisons. No theory, upheld arms have blocked incoming fire.

    More commonly, a bullet may need to penetrate laterally through a forearm/radius/ulna or, through a bicep and/or humerus, before striking as assailant in the COM. It helps to have a bullet that can still pass through an appendage under those circumstances (between 2 and 6 inches wide depending upon fat and muscle composition) and still possess enough penetrative ability to make it through a ribcage/sternum and into the lungs, heart, or the CNS.
     
  11. bullseye308

    bullseye308 Member

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    I’m barely knowledgeable enough to join this discussion, but it seems from most of the comments that we are only talking about one round fired. I don’t know about anyone else, but I would expect I’d fire at least 3 and reassess if more are needed. I thought we were years past the discussion of “one shot stops” especially with most folks(myself included) carrying 9mm’s. I train to put 3 rounds in a close group to get the most efficient incapacitation to stop the threat. More to follow as needed probably doubles till the treat is stopped.

    I finally get the ballistic gel thing that started this, it is just a common reproducible medium that everyone can use to compare rounds. Thanks to all who contributed. That’s why I love it here.
     
  12. JohnKSa

    JohnKSa Moderator Staff Member

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    I'd recommend against training to fire a fixed number of shots and then stopping to assess. Shoot until the threat goes away, whatever that means in the situation and whether that means 10 shots or NONE. You should be constantly assessing the situation, not shooting, stopping, assessing, shooting some more, stopping to assess again, shooting some more, etc. You can see what's going on while you are shooting. Shoot until the threat is neutralized and then stop.

    Also, it's a mistake to confuse the number of shots fired with the number of hits made. While it is possible to hit with every round fired in a self-defense situation, statistics from LE shootings suggest that hit rates of about 30% might be more realistic.
     
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  13. Texas10mm

    Texas10mm Member

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    Well, according to at least one Democrat Elk Skin is bullet proof.

    http://whackstarhunters.com/democratic-candidate-believes-elk-are-bullet-proof/
     
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  14. Madcap_Magician

    Madcap_Magician Member

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    This is both the source of the question and its answer. Each shooting is individual, whether defensive, offensive, or of an animal in a hunting or control shoot. I've always thought that we'll never get beyond "Well, probably this bullet in this caliber from this gun will work, all else being equal."

    Which is difficult because all else is not equal.

    I don't think this is an accurate assessment. It's certainly possible that if someone is facing away from you that this might come up in court, but A) if you shoot someone regardless of their orientation toward you, you're going to have to explain to the police and maybe a grand jury how they posed a threat to you, and B) what physical orientation a person has is not related to whether or not they posed a threat of death or great bodily harm to you or another at the time they are shot.
     
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  15. rpenmanparker

    rpenmanparker Member

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    This discussion is not peculiar to firearms and ballistic gel. In many scientific pursuits a representative, standard test medium and/or method is used to qualify something for a particular use. No one skilled in that technology thinks the behavior of the test medium and method will be or is even supposed to be identical to the real world use situation. My own experience includes testing plastic devices for use in medical and rigid packaging applications. The results of my lab tests accurately predicted the behavior of the devices in real world use, but they looked nothing like the actual real world results. PROPER USE OF THE TEST MEDIUM AND METHOD ASSUMES KNOWING HOW THE RESULTS IN THE TEST PREDICT RESULTS IN REAL WORLD USE. That is the key.

    So superimposing that understanding on this topic, the FBI never said that 12-18" of bullet penetration in a human target was ideal or even required. They said, implicitly or explicitly, that 12-18" of penetration in ballistic gel CORRELATES to an effective hit on a human target. You simply can't talk about gel being or not being the same as the human body. That was never the stipulation. Think of it this way: the FBI is saying that based on historical data, bullets which penetrate gel 12-18" have a high probability of killing a human without exiting the body. They aren't saying anything about the specific depth of penetration of the human body.
     
  16. Tirod

    Tirod Member

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    Two things to note about the Miami shootout, the ballistics testing to improve ammo plays right up to what gun forum posters like to talk about. The tactical failures went much further and it changed a lot of what the FBI did in future responses. There were plenty of in depth exams of how the agents could have handled things better - same as the LA bank robbery, which eventually resulted in having rifles more available to do a rifle's job.

    Those tactical improvements aren't heralded as much, partially for operations security - why let the perps in on it - and partly because forum posters don't focus on them. There isn't much tangible there to hang a hat on.

    I highlighted the FBI's point about overpenetration - If you are going to miss most of your shots, then what's the worry about the few which pass thru? Bullets flying thru the neighborhood will be coming from the perps guns, too. Stop him shooting and things will be safer for everybody. But on internet forum boards "everybody" always throws up that YOUR bullets are the main liability issue. No, not really. You could say being perceived as weak and an easy mark was just as much culpability. I won't propose open carry as a solution for that, but when aggressors get the idea that you are profitable and low risk, elevating your appearance on the social scale of being less a target would seem prudent. Then no guns at all are more likely.

    Dont forget that cops run toward the sound of gunfire and plan difficult confrontations (or are supposed to prepare for them.) We don't, which means when the agents went to confront the perps, we would be elsewhere - at home. Don't draw too many conclusions about what we should do when the case involves something we aren't supposed to do in the first place, especially an incident where unfortunately professionals made bad decisions.
     
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  17. JohnKSa

    JohnKSa Moderator Staff Member

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    Whether they say it or not, it's implied. The entire reason that ballistic gel was developed was to mimic the average density of human tissue so that shots into ballistic gelatin would be representative of what expansion and penetration would be expected ON AVERAGE, if a number of shots were made with that loading into human tissue. That's what it was developed to do and it does it well enough that no one has come up with anything better yet.
     
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  18. Picher

    Picher Member

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    I've been a shooter, hunter, and firearms instructor and have probably killed over a hundred mammals of various sizes/shapes, but never a person. However, advice I read about shooting an advancing attacker in the pelvic region makes sense, as it makes them drop, obviously in considerable pain, and if still combative, a relatively immobile target. A little low gets them in the jewels, and a little high, in the intestines, but could also reach the spine.

    Most centerfire handgun rounds shot into the breastbone area may not result in a quick kill. The heart, if hit can result in the assailant going several yards before collapsing. I've seen deer run 90 yards with the heart completely shot-out, but tend to drop quickly if shot in the spine or shoulders. That doesn't apply much to shooting humans facing you, but if sideways, opens both lungs to a lethal shot.

    I've also seen deer shot with a .44 Magnum handgun that ran many yards until bleeding out. (I don't hunt with handguns anymore.)

    I sincerely hope that I don't have to shoot anyone, anytime.
     
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  19. rpenmanparker

    rpenmanparker Member

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    There are too many differences between gel and the human body for your explanation to be correct. Correlation of two similar but different media is the only possible answer. Gel has the advantage of being standardized and reproducible, but it is not anything like the human body as a whole. The size of a gel block is more a matter of convenience and ease of preparation and use than it is a resemblance to the body.
     
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  20. Charliefrank

    Charliefrank Member

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    Weren't the Strasburg tests done years ago performed on live goats to help determine bullet performance?
     
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  21. JohnKSa

    JohnKSa Moderator Staff Member

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    There are a lot of differences between gel and the human body; however, in spite of those differences, my explanation is correct.

    Ballistic gel mimics the average density of human tissue and does it very well. If a significant number of rounds were fired into human tissue, the average penetration of the rounds would agree with the results from gelatin testing. That is true even if it seems counterintuitive, and regardless of the differences between gel and human tissue.

    This study, for example found that autopsy penetration results on human torsos showed the same average penetration as ballistic gel testing results.

    http://www.ar15.com/ammo/project/Fackler_Articles/winchester_9mm.pdf

    Some thought will indicate that we should expect this result. We know that the FBI is very picky about its ammunition--and we know that they don't specify bone simulant used in FBI ammo testing. This means that one of the following conclusions true: The FBI doesn't care about/know about the presence of bones in the human body, or the FBI is aware of bones but realizes that penetration data from gel already gives them the information they need. It's not hard to see which conclusion makes more sense.
     
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  22. rpenmanparker

    rpenmanparker Member

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    Or the FBI has a large data set with mortality and penetration results that it can correlate with bullet performance in gel. Not the same numbers for humans and gel, but correlated numbers. So they have found a bullet that has 15 inches penetration in gel kills folks really well without passing through. It just doesn’t matter what the actual numbers are in humans as long as the effectiveness result is predicted by the correlation with gel.
     
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  23. RetiredUSNChief

    RetiredUSNChief Member

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    I don't think "kills folks really well without passing through" was ever a criteria.

    Speaking as an engineer, I know it wouldn't be MY criteria, especially if we're talking about specifications like "15 inches penetration".

    I just stuck a 12 inch ruler under my armpit up against my desk chair as I was typing here. The ruler extends past my chest by 3 inches. There are plenty of people whose body thickness is less than 15 inches, so killing "without passing through" obviously isn't a criteria.

    While ballistics gel does mimic human soft tissue on average, as @JohnKSa has said more than once, the OTHER very important factor here is that ballistics gel offers an actual calibrated standard by which ballistics testing may be performed by ANYBODY, ANYWHERE, with ANY type of ammunition.

    There are a great many factors which influence terminal ballistics...bullet design, velocity, mass, trajectory through tissues, deformation upon impact, jacketed, unjacketed, etc. Having an actual, calibrated ballistic gel eliminates the various factors/uncertainties of the target during controlled testing, enabling people to accurately produce AND REPRODUCE penetration data on any number of ammunition types.

    THIS is the real "engineering marvel" of this.

    You, I, and anybody else can mix up a batch of ballistic gel at the correct temperature, do a calibration check on it, and conduct testing anywhere in the world which will produce the same data for the same ammunition.
     
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  24. JohnKSa

    JohnKSa Moderator Staff Member

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    I suppose that's a possible explanation, but it certainly doesn't seem to be a very likely one given the results of the study which showed identical average penetration in gel and human torsos (which, of course, include bone, skin and various types of tissue).
     
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  25. Odd Job

    Odd Job Moderator Staff Member

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    One small correction, the study excluded any shots involving bone.

    Before I hitch my wagon to the Wolberg paper I want to know:

    1) What tissues were traversed in each of the 25 valid shots. "Torso" means chest and abdomen and there is a big difference between lung tissue and the abdominal organs, even if bone is excluded. They opened the door to this line of questioning in the paper by posting differing expansion diameters of bullets fired in pig "abdomen" vs pig "muscle" vs water.
    2) More variables. What was the range of fire? Were all the service weapons the same in terms of barrel length? What influence did clothing play? What was the angle of incidence for each shot?
    3) How did the pathologist measure the penetration length? Specifically I am interested in trajectories that aren't straight, such as if a round is deflected by the diaphragm. It can go the other way too: you can get a false increased penetration distance if the bullet slips between two tissue planes.

    Smells like a "massaged" selection to me.
     
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