Why do manufacturers make underpenetrating loads for defense?


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Skribs
May 7, 2012, 12:02 PM
I've noticed a lot of loads that are designed for personal defense, put out by a lot of companies, either fall short of or barely meet the 12" penetration requirement in ballistics gel. IIRC, the FBI recommends 12-18", and I'd personally prefer something on the later end. It seems form comments on the various ammo that a lot of people agree with me. Too often I see "it's a good idea, but the load is light and likely to underpenetrate" or "it only has 11 inches of penetration, I wouldn't use it."

Do these companies not test their products before-hand, or do they go by a different requirement?

For me, it's pretty much gotten to the point where I just carry the heaviest bulk hollowpoint I can find.

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allaroundhunter
May 7, 2012, 12:06 PM
The 12" minimum is because law enforcement engagements oftentimes include shooting through barriers. Civilian SD encounters rarely do.

There is no part of the human body that requires a bullet to travel 12" to reach vital organs, so I don't require my self defense rounds to pass that test.



ETA: Forget my answer, Sam wins again...

Sam1911
May 7, 2012, 12:21 PM
And, because for every thread out there asking for loads that meet the minimum, there are two worried about "overpenetration."

Hard to tell which thing each shopper might be worried about so it's best to make both.

;)

Certaindeaf
May 7, 2012, 12:29 PM
I think that 12"+ "rule" and the 10mm and .40 came from the Florida fiasco. Gotta blame something.

303tom
May 7, 2012, 12:43 PM
Because they don`t want to over penetrate & poke holes in bystanders.............

loose noose
May 7, 2012, 12:53 PM
In the casino business over penetration leads to multiple civil suits, in the case where a projectile would penetrate thru one body (the perpetrator) and strike a second innocent bystander. I prefer a light projectile that will expend it's energy in the intended target. I also use this round as my home defense load. I prefer Corbon 135 grain in the .40 S&W and Corbon in the 110 grain in the .38 Spl. I also use the 185 grain Corbon in my .45 ACP. My wife uses Hornady Critical Defense 90 grain in her .380 auto.

Cosmoline
May 7, 2012, 01:01 PM
There is no part of the human body that requires a bullet to travel 12" to reach vital organs, so I don't require my self defense rounds to pass that test.

Well that's the theory, but bullets IRL don't always behave as they are supposed to. They veer off, get lost in fat layers, get mired down by layers of clothing, and lose velocity before reaching anything vital. That's why you'll find many reports of suspects surviving many hits from handgun rounds from 9x19's to .45 ACP.

Full penetration offers several major advantages. First of all, it creates two holes for blood to come out of. This doubles the flow of blood (at least) and thereby hastens shock. It also helps ensure that the round has enough power to continue penetrating straight and not lose juice and start to veer off. With the right bullet design, it also dramatically increases the lethality by creating a much larger exit wound.

These are all among the reasons why through-and-through penetration is seen as a positive good for hunting. And there is no question that a round powerful enough to penetrate straight, expand, and exit, is far superior at stopping a threat than one which enters, slows fast and stops.

However, there are some tradeoffs involved. Handguns are generally weak and underpowered. To make a round powerful enough to offer the full expansion and through-and-through penetration, you have to amp up the charge and that means more recoil. We're really talking about bullets in the range of a .357 Maximum or .44 Magnum, and that's just not terribly practical for real life use in a CCW platform.

Ironically, and ingeniously, the handgun bullet makers have turned the disadvantage into an advantage. They've turned the *MINIMUM* penetration depth figures into an *IDEAL* penetration depth. Which it was never supposed to be.

will expend it's energy in the intended target

This is an example of how successful the marketing scheme has been. In reality, that's just sales spin. "Expending its energy in the target" is really admitting the BULLET STOPS MID-WAY. And a bullet that stops is a bullet that stops working.

Overpenetration is another way they've whipped up fear to increase sales. While it's happened before, it's vastly more likely that a bystander will be injured by a CLEAN MISS than a round that overpenetrates. Furthermore it's easy to control the performance of the round IF you have sufficient velocity. So you can ensure through bullet design that upon exploding out in the exit wound, the bullet will be in pieces, but only if you have the energy to play with. A slowing, stopping bullet won't expand let alone explode. Which of course favors use of the AR carbine or similar long gun over any handgun. You minimize danger to third parties by reducing total rounds fired and increasing the effectiveness of the rounds you do fire.

Personally, I've gone back to good old-fashioned soft lead projectiles for handgun use. They penetrate better than most higher-tech rounds and have a reasonable track record. They're still very underpowered and far inferior to a long gun, but for emergency purposes they're about the best that can be done.

brickeyee
May 7, 2012, 01:19 PM
do they go by a different requirement?

There is actually no "requirement" they must meet.

It is called a free market.

coloradokevin
May 7, 2012, 03:19 PM
I've noticed a lot of loads that are designed for personal defense, put out by a lot of companies, either fall short of or barely meet the 12" penetration requirement in ballistics gel. IIRC, the FBI recommends 12-18", and I'd personally prefer something on the later end. It seems form comments on the various ammo that a lot of people agree with me. Too often I see "it's a good idea, but the load is light and likely to underpenetrate" or "it only has 11 inches of penetration, I wouldn't use it."

I think Sam hit the nail on this one... the less effective bullets are sold to satisfy the desires of a market segment that is terrified by the idea of over-penetration. But, reality is that a bullet that penetrates deeply enough to do its job is going to be a bullet that can also penetrate wall board and other such objects (as such, hitting your target does minimize this risk a bit).

The 12" minimum is because law enforcement engagements oftentimes include shooting through barriers. Civilian SD encounters rarely do.

There is no part of the human body that requires a bullet to travel 12" to reach vital organs, so I don't require my self defense rounds to pass that test.

Except that the 12-18" penetration goal is AFTER the bullet has struck intermediate barriers such as windshield glass, etc (in other words, in LE we aren't looking for a deeper penetrating bullet because of these barriers, we are looking for that much penetration even IF we penetrate those barriers). As such, the only difference in what law enforcement may require is that their bullet still needs to maintain that level of effectiveness AFTER striking those barriers. The goal on-target is still 12-18" of penetration in calibrated (I believe 10%) ballistic gelatin.

Bullets do funny things. Sometimes a bullet will get deformed/clogged after going through a barrier (be it clothing, wall board, windshield glass, etc), and will then fail to expand, thereby penetrating more deeply. Other times a bullet may come apart and fail to penetrate as expected after striking an intermediate barrier (my department switched our rifle ammo after observing this trend during shots through barriers -- I was at the workshop myself, and wasn't thrilled with seeing 7" penetration from a .223).

As an example of why the 12-18" of penetration in calibrated ballistic gelatin guideline is used, consider the following shot:

An adversary that weighs 350 lbs is facing you from the side. The only shot you have toward the vitals involves shooting through the arm, before hitting the torso itself. First, you may very well need at least 12 inches of penetration on such a shot against a person who's that big, especially if you have to shoot through an arm to get to the vitals. Secondarily, you will quite possibly hit bone. The 12-18" is based purely on gelatin, whereas bone will most certainly change the real world performance.

In our wound ballistics workshop (which was put on by ATK) we conducted the tests in a standardized manner. The intermediate barriers consisted of things like windshield glass, wall board, light clothing, and heavy clothing, all per the FBI protocol. But, we also shot the gelatin without going through an intermediate barrier. The goal in each test was to land in the 12-18" penetration range.



I prefer a light projectile that will expend it's energy in the intended target.

The whole concept of "energy transfer" with a bullet is meaningless. Don't get me wrong, I know you aren't the one who pioneered this idea. It has been talked about at gun store counters and in the halls of gun shows for years. Some companies even market to the idea. Put as simply as I can say it, the size and depth of the hole made by the bullet is what matters here (these things can be determined by the velocity of the bullet, the size of the bullet, the expansion of the bullet, and how the bullet stays together after making contact).

A bullet that stops short after a hit simply stops. It doesn't deliver any more practical energy to the subject than the bullet that zips on through. The idea of "knock down power" is great for marketing, but a poor thing to bet your life on. Simply put, a bullet doesn't just knock you down.

Loosedhorse
May 7, 2012, 03:38 PM
There is actually no "requirement" they must meet.There you go.

The FBI came up with a standard for their agents, given the type of encounters they have. Most LE departments don't have the resources of the FBI, and said "close enough--we'll have what they're having."

To the extent that your encounter differs from the average FBI one, you might want a different ammo standard.

If an FBI round over penetrates and injures someone, well, the injured now has to sue the federal government; even if there is a judgment, the agent who fired will not have to pay. However, if your bullet over penetrates and injures someone, there are fewer barriers to suing a private citizen, and you'll get the bill.The whole concept of "energy transfer" with a bullet is meaningless.Well, that's not strictly accurate. Everyone (I think) agrees that once energy levels reach those of rifle rounds, temporary cavitation (driven by velocity and energy transfer) becomes an important wounding mechanism, especially if coupled with bullet fragmentation.

Part of the disagreement on handgun energy importance stems from the phenomenon of non-fatal stops. Statistics seem to indicate that most persons shot with handguns survive, suggesting the attackers among those survivors stopped before being wounded in a vital organ and bleeding out (or receiving a fatal CNS hit). We also have the anecdotal evidence that low-energy-deposition rounds (like the old .38 Special 158 gr RNL) were ineffective at ending fights; while high-energy (like the Illinois State Police 9mm+P+) rounds were anecdotally very effective.

So, if one focuses on the idea that a bullet must under all circumstances penetrate to a vital structure to produce a "dependable" stop, you may decide that energy doesn't matter. Even if it seems that striking a vital structure is not necessary to end the majority of gun fights, or if there is anecdotal evidence that high energy handgun rounds stop fights better than low energy ones.

Good news: modern loads tend to give us both good penetration and good energy deposition, so you don't have to choose. We still have room to argue, though, about whether 11 inches of penetration is actually worse than 12 inches; and whether 14 is better than 12. Mostly because we have no good data to show us whether an extra two or three inches of penetration make a significant fight-stopping difference.

Cosmoline
May 7, 2012, 03:43 PM
low-energy-deposition

What energy are you talking about? It's not as if a bullet that stops mid way sends some kind of shockwave in *front* of it after stopping. The round simply loses its juice and ceases to do any further damage. Whether or not that damage is sufficient depends on what tissues it has destroyed up to that point.

I've never seen support for the notion that the raw foot pounds of the round, absent actual tissue damage, serve any role at all. Of course if you have enough energy you can use it to expand hollow points and increase tissue damage. But a lot of handgun rounds don't have enough, and end up with HP's that act like an air brake.

Skribs
May 7, 2012, 03:48 PM
Loose Noose, I think security applications in heavily populated areas (such as a casino, mall, travel terminal) have different factors from the home defense or personal defense scenario. If I was in the situation where I knew there would be hundreds of bystanders, I would want something that stops inside the assailant.

On the other hand, my complaint was mainly that I think some of the advancements in expanding bullet design (such as methods to defeat hollow-point clogging) are hindered by the fear of overpenetration. You look at EFMJ ammuntion or most of the polymer-tipped hollowpoints on the market, which I think are interesting designs, and the reason people don't want them is lack of penetration. I actually bought the Glaser Safety Slug koolaid but came to my senses and had an expensive range session to get rid of them.

jmr40
May 7, 2012, 04:40 PM
The 12" minimum is because law enforcement engagements oftentimes include shooting through barriers. Civilian SD encounters rarely do.

There is no part of the human body that requires a bullet to travel 12" to reach vital organs, so I don't require my self defense rounds to pass that test.



Civilians are just as likely to have to penetrate barriers as LE in a shooting. A bullet may, or may not need to penetrate 12" to reach vital organs. It depends on the angle of the shot. Even then it has to completely penetrate vital organs, not just reach them.

Bad guys don't stand still with bulls-eyes painted on their chests while you shoot them. They are ducking, running, squatting, hiding behind barriers, turned to one side and making it as difficult as possible for you or a LE officer to hit them. Your bullet may have to penetrate a bicep muscle and 3 layers of clothing before even striking the chest from a side shot.

joecil
May 7, 2012, 04:48 PM
Well as someone who has been hit by a wayward bullet that over penetrated I can tell you when I carry SD loads it is a JHP and I don't want nor need more than 12" of penetration. Besides a fmj round which will over penetrate doesn't stop as quickly as one that expands when it hits soft tissue. Oh and I was hit by a 38 after it passed through anothers upper body then a table 50' from the shooting and lodged against the bone in my forearm.

Loosedhorse
May 7, 2012, 05:12 PM
What energy are you talking about?The bullet's kinetic energy, which (if the bullet stays in the body) is expended by bullet deformation; direct tissue injury; tissue displacement and tearing (at higher energies); heat; and a small amount of imparted kinetic impulse to the body.I've never seen support for the notion that the raw foot pounds of the round, absent actual tissue damage, serve any role at all.This is a little like saying you've never seen evidence that a bullet, absent actual tissue damage, serves any role at all. At rifle energy levels, tissue tearing (caused by cavitation) can be the predominant mechanism of injury.

And then of course, there is the anecdotal evidence of the ISP 9mm vs the NYPD .38 RNL. To the extent that there is "no evidence" that energy makes a difference, there will also be "no evidence" that it does not; so it will boil down to which assumption you prefer.Civilians are just as likely to have to penetrate barriers as LE in a shooting.Is there data that supports your opinion?

The FBI understandably (given their routine need to approach vehicles) specified ammo tests using automobile glass and sheet metal. I think my likelihood of shooting through those barriers is lower than theirs, but YMMV.

huntsman
May 7, 2012, 05:51 PM
Why do manufacturers make underpenetrating loads for defense?

I don't think they do it on purpose:) it's just they're in the business to sell cartridges and the FMJ doesn't offer the marketable hype jhp does.

the best sales pitch is to create a problem then sell the solution.

you could always carry FMJ if penetration is a concern, I do.

Skribs
May 7, 2012, 05:54 PM
Huntsman, I'm not talking FMJ vs. JHP. I'm talking a light bullet that isn't designed to be hot (or a really light bullet in +P) that penetrates less than 12 inches. They could get better penetration out of a heavier bullet using otherwise the same bullet design.

Certaindeaf
May 7, 2012, 06:01 PM
I don't think they do it on purpose:) it's just they're in the business to sell cartridges and the FMJ doesn't offer the marketable hype jhp does.

the best sales pitch is to create a problem then sell the solution.

you could always carry FMJ if penetration is a concern, I do.
Have you ever shot a rabbit or deer? Never mind.

Cosmoline
May 7, 2012, 06:44 PM
They could get better penetration out of a heavier bullet using otherwise the same bullet design.

And it would cost them more in lead and copper and recoil more. They've made a DRAWBACK into an ASSET. It's brilliant, really. It's the same as selling a car that can't go over 35 MPH as a state-of-the-art marvel designed to keep you extra safe.

browningguy
May 7, 2012, 07:04 PM
I love reading all the experts in physics here.

You may be in love with the idea of overpenetration and shooting a minimum of 12-16" through gelatin, and that's fine. But it's no more correct than someone that prefers less penetration.

It's not that the bullet "stops working", or that someone is being "sold" something, or the manufacturers are trying to save .0007 cents per bullet. It's simply that some people disagree with your "opinion". Get over it and let people use what they want.

huntsman
May 7, 2012, 09:09 PM
Have you ever shot a rabbit or deer? Never mind.
lots why??

coloradokevin
May 7, 2012, 09:20 PM
Well, that's not strictly accurate. Everyone (I think) agrees that once energy levels reach those of rifle rounds, temporary cavitation (driven by velocity and energy transfer) becomes an important wounding mechanism, especially if coupled with bullet fragmentation.

Yes, indeed. But that's not the "energy transfer" that people are speaking of when they talk about the advantage of having a bullet stay in the body and "dump all of its energy", rather than "passing right through and doing nothing".

High velocity rifles are truly devastating when compared to typical defensive pistols. Yes, they are higher energy. But, whether that bullet stops in the body or goes on through is largely irrelevant, aside from considering what structures are damaged by that bullet. In other words, if a .223 stops in the body mere millimeters from the backside, you don't gain an "energy transfer" compared to the same bullet that goes all the way through (that myth has been stated repeatedly for years in some circles).

huntsman
May 7, 2012, 09:22 PM
Huntsman, I'm not talking FMJ vs. JHP. I'm talking a light bullet that isn't designed to be hot (or a really light bullet in +P) that penetrates less than 12 inches. They could get better penetration out of a heavier bullet using otherwise the same bullet design.
when the discussion of penetration comes up it's usually FMJ vs JHP my bad, I don’t believe there’s much difference between a 185gr or 230gr jhp in my .45acp.

Maybe I'm missing something or is your issue caliber specific?

I have some of the new whiz-bang SD stuff but I'd never buy frangable and I'm not running out to spend money on Critical defense

Loosedhorse
May 7, 2012, 09:50 PM
In other words, if a .223 stops in the body mere millimeters from the backside, you don't gain an "energy transfer" compared to the same bullet that goes all the way throughActually, you do gain "energy transfer." If a bullet exits, then whatever kinetic energy it has on exit did not get transfered to the target. Therefore--assuming both bullets initially had the same kinetic energy--tissue was stretched (and torn) by temporary cavitation less by the bullet that exited with some residual kinetic energy than by the bullet that "dumped" all its energy into tissue cavitation.

For pistols, we're dealing with two unanswered questions. I mean unanswered experimentally, since we don't have actual, carefully collected data. Both questions are answered--in all sorts of different ways--by various competing theories. Unfortunately, without the data, we can't be sure which competing theories to discard.

The two unanswered questions are: is greater energy transfer (at handgun energy levels) an important factor in stopping most attackers; and, is the difference between projectiles that penetrate 11, 12 or 14+ inches actually important to private citizen SD gunfights?

allaroundhunter
May 7, 2012, 09:53 PM
In other words, if a .223 stops in the body mere millimeters from the backside, you don't gain an "energy transfer" compared to the same bullet that goes all the way through (that myth has been stated repeatedly for years in some circles).

It isn't a myth, it is fundamental physics.

Rampant_Colt
May 7, 2012, 10:33 PM
I've noticed a lot of loads that are designed for personal defense, put out by a lot of companies, either fall short of or barely meet the 12" penetration requirement in ballistics gel. IIRC, the FBI recommends 12-18", and I'd personally prefer something on the later end. It seems form comments on the various ammo that a lot of people agree with me. Too often I see "it's a good idea, but the load is light and likely to underpenetrate" or "it only has 11 inches of penetration, I wouldn't use it."

Do these companies not test their products before-hand, or do they go by a different requirement?

For me, it's pretty much gotten to the point where I just carry the heaviest bulk hollowpoint I can find.


You'll find your answer HERE (http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/index.htm)

Skribs
May 7, 2012, 10:54 PM
You may be in love with the idea of overpenetration and shooting a minimum of 12-16" through gelatin, and that's fine. But it's no more correct than someone that prefers less penetration.

If the bullet doesn't penetrate deep enough to reliably hit vitals (assuming it was aimed at the vitals), then it is much less likely to cause an involuntary stop. That isn't opinion.

Huntsman,
180 grain is already getting pretty heavy. I'm talking more about the .38 SPL rounds which use 90 grain bullets instead of 158 grain, or 9mm rounds that use 115 grain bullets instead of 147.

writerinmo
May 7, 2012, 11:02 PM
I have one firearm that I would seriously be concerned about overpenetration, but it's doubtful that I would grab my Mosin over the AK or any of my pistols.

coloradokevin
May 8, 2012, 04:19 AM
In other words, if a .223 stops in the body mere millimeters from the backside, you don't gain an "energy transfer" compared to the same bullet that goes all the way through (that myth has been stated repeatedly for years in some circles).It isn't a myth, it is fundamental physics.


Let me edit my last statement to speak more precisely: In other words, if a .223 stops in the body mere millimeters from the backside, you don't gain any MEANINGFUL "energy transfer" compared to the same bullet that goes all the way through (that myth has been stated repeatedly for years in some circles).

The idea that a bullet stopping within the body will transfer a more meaningful amount of energy to the subject than a bullet that exits the body is not supported by any ballistic study I've ever seen. This conjecture has been tossed around for years, but the bullet doesn't kill because of energy transferred by failing to fully penetrate; the bullet's energy won't "knock down" the prey.

I'm not a physicist, and I can't give you a perfect scientific explanation of this fact. But, here it is in layman's terms in a video (as they state, per Newton's 3rd law, that energy is also transferred to the shooter in terms of recoil -- I'm sure in reality the weapon system absorbs some of that energy). Has recoil energy ever had a meaningful effect on your ability to stand?:

http://youtu.be/QCzD5uhSViY

There are tons of articles on this subject, if you look for them. Here's a quick find over on Chuckhawk's site:

http://www.chuckhawks.com/myth_muzzle_energy.htm


Put another way, by the bullet energy argument, a fast moving .223 round that exits the body and continues to move at a high velocity is a bullet that has failed to transfer much energy to its target. On the other hand, a 9mm bullet that stops within the adversary has managed to transfer all of its energy to the subject. But, the rifle bullet has clearly proven itself to be a more lethal round.

Nevertheless, for the purposes of this thread it seems more important to find a bullet that has adequate penetration capability, but not so much penetration that it causes unnecessary risk to parties who aren't involved in the gun fight. That can take us back to the good old 12-18" of penetration argument (if you support that FBI's study on this subject).

Loosedhorse
May 8, 2012, 10:00 AM
you don't gain any MEANINGFUL "energy transfer"...

The idea that a bullet stopping within the body will transfer a more meaningful amount of energy to the subject than a bullet that exits the body is not supported by any ballistic study I've ever seen."Meaningful" cannot be determined by ballistic studies. They have no way of determining if a .223 delivering all 1250 ft-lbs (typical) of its energy to its target is "more" or "equally meaningful" than if it delivers only 1100, or only 950 ft-lbs of its energy.

To determine that, we'd need a database of how attackers respond when being shot with the same caliber round but with bullets designed to either stay inside the body or to over-penetrate with given residual energies.

One often hears that bullet velocities "over 2000 fps" are needed to change the main wounding mechanism from direct bullet-crush injury to the more distant injury caused by cavitation and bullet fragmentation. Perhaps this is the source of the idea that any energy deposited in the body beyond whatever a .223 at 2000 fps would produce is "not meaningful."

But that doesn't make sense. If that were so, why would we standardly use a .223 round going 1200 fps faster? If tissue cavitation is the main mechainsm of injury, and is related to energy deposition, how can we--without experimental data on stopping attackers--determine how "meaningful" any given loss of energy transfer is?

(The question "how can we--without experimental data on stopping attackers--determine how 'meaningful' any given loss of penetration is?" also applies.)

BTW, I like the article you pointed to a Chuck Hawks. But the significance of muzzle energy vs. penetration is different when the animal hunted is a prairie dog or a Cape buffalo--and of course the human attacker is in the middle somewhere. And even with a Cape buffalo, my guess is that most hunters would prefer a high-energy-deposition round that penetrates well compared to a low-energy-deposition round that penetrates well.

Skribs
May 8, 2012, 11:03 AM
LH, on the .223 round, I know the Army uses it at that velocity because the specific bullet needs to be going 2700 FPS to reliably fragment, and 3200 FPS makes that a reliability at distances they will expect to be shooting.

Bullets do need to dump some energy in order to cause the cavitation. Some of those rounds that tumbled late on the AR-15 link at the top of page 2 didn't cause much of a wound tract until after several inches of penetration. However, they also caused less when they slowed down. A round that stops is a round that slowed down way back.

With a non-rifle round, you're not even worried about the cavitation effects, and the energy transfer idea is null. They deal their damage by poking holes. If the bullet stops, it poked less of a hole. If it stops short of vital organs, it just caused a flesh wound.

Driftertank
May 8, 2012, 11:06 AM
If a .223 bullet stops within millimeters of entering the body, it likely had much less energy going in than a round that went clear through. If they started out with the same energy, and bullet design is what caused the rapid stop, there WILL be some massive localized tissue damage from the propagation of the energy through the tissue...the energy has to go somewhere. But there is minimal risk of exsanguination, and unless it impacted close enough to a vital organ to damage it, you likely only caused some muscle to turn to goo. That's what hydraulic shock is all about.

Problem is that handgun rounds don't have enough energy to cause gooification. They basically only damage tissue they actually come in contact with. So the "ideal" handgun round would impact, expand as much possible, and travel clear through the body, expending all it's energy, dropping harmlessly to the ground on exit. Since that won't happen, i personally prefer a bullet that gets big and drives deep. Other opinions welcome.

Shawn Dodson
May 8, 2012, 12:02 PM
The 12" minimum is because law enforcement engagements oftentimes include shooting through barriers. Civilian SD encounters rarely do.

There are many everyday situations in which a private citizen may have to shoot through concealment to land a hit on an attacker, including circumstances identified in “A Word of Caution about Hornady’s Critical Defense Handgun Ammunition” at - http://www.firearmstactical.com/tacticalbriefs/2006/04/main.htm

There is no part of the human body that requires a bullet to travel 12" to reach vital organs, so I don't require my self defense rounds to pass that test.

A bullet can lose as much as 30% of its total penetration potential after it first perforates an arm. Thus a bullet that normally penetrates 10” may now only penetrate 7”. If the bullet penetrates 4" of arm then it may possess only 3" of remaining penetration potential to penetrate the body after it first passes through the arm. Depending on the attacker’s angle and body position this may not be enough penetration to reach and damage vitals.

Full penetration offers several major advantages. First of all, it creates two holes for blood to come out of. This doubles the flow of blood (at least) and thereby hastens shock.

The “two holes creating greater blood loss” theory is more myth than reality. Bleeding produced by a handgun bullet is mostly internal – blood leaks into the thoracic (chest) and abdominal cavities – there may be very little blood that actually leaks outside the torso.

If an FBI round over penetrates and injures someone, well, the injured now has to sue the federal government; even if there is a judgment, the agent who fired will not have to pay. However, if your bullet over penetrates and injures someone, there are fewer barriers to suing a private citizen, and you'll get the bill.

Many cases of “over-penetration” are the result of hits along the periphery of the torso, in which the penetration path through-and-through is less than the penetration path encountered during a solid center-mass hit.

Hence you can choose a bullet that penetrates 8” but if it hits along the periphery of the body it, too, may “over-penetrate”.

Anecdotal reports of “over-penetration” usually do not include a description of the bullet’s penetration path through the body.

Skribs
May 8, 2012, 12:16 PM
Many cases of “over-penetration” are the result of hits along the periphery of the torso, in which the penetration path through-and-through is less than the penetration path encountered during a solid center-mass hit.

Also if you miss, you "overpenetrate" by not hitting anything.

Cosmoline
May 8, 2012, 12:18 PM
Energy which does not damage tissue is not meaningful.

Bleeding produced by a handgun bullet is mostly internal

That depends on what you hit. But there's no question, medically, that a second hole for blood to exit from (preferably a larger one) accelerates blood loss and brings on shock faster. That's why first aid attempts to plug those holes. It's also a major reason for wanting two holes on game animals. Anyone who's seen the big gory exit hole with lots of blood oozing out of it can attest to that.

I have one firearm that I would seriously be concerned about overpenetration, but it's doubtful that I would grab my Mosin over the AK or any of my pistols.

Actually the Mosin provides more than enough power to do pretty much anything you want. If you want a 3,200 fps exploding SP, you can easily rig one. Whereas, for example, a low velocity heavy round from a handgun will keep on trucking much further through barriers.

Certaindeaf
May 8, 2012, 12:22 PM
Back in the olden days, manufacturers went light and fast (super-vel etc) because handgun bullet design was in its infancy. Of course, the various 240gr .44 mag HP's going at 12bajillionfps wouldn't open up on game on a bet though.

Shawn Dodson
May 8, 2012, 12:25 PM
But there's no question, medically, that a second hole for blood to exit from (preferably a larger one) accelerates blood loss and brings on shock faster. That's why first aid attempts to plug those holes. Medically, a chest tube is inserted to drain blood to keep internal bleeding from collapsing the lungs. If blood flowed are readily out the external bullet hole as you suggest the chest tube wouldn't be necessary.

First aid to the to the bullet holes on the outside of the torso doesn't stop internal bleeding.

Cosmoline
May 8, 2012, 12:30 PM
There often isn't an exit wound, precisely because so many handgun bullets stop short. And while internal bleeding is a potential threat, you're talking about someone who's already survived long enough to get a chest tube. That's not a bullet that worked well enough. If the blood drains out faster, then the circulatory system depressurizes faster and shock sets in. You don't have to deal with a lung collapse from internal bleeding because you're dead. And conversely a bad guy who's suffering from slowly accumulating blood in the cavity is still going to be able to shoot back. You want to drain his blood as fast as possible or get a CNS hit because those are the only reliable ways to stop him.

It's why hitting the heart or a major artery is so often fatal, because so much blood is lost so quickly.

But you're absolutely correct that single-hole small caliber handguns don't tend to produce a lot of blood. That's one reason they don't work too well. I remember going right past a dude that had just been shot a minute earlier in a drive-by with a small caliber handgun. He was just sitting there holding his gut. I thought he was intoxicated and went on. There was no blood, no nothing. And he survived after a trip to the hospital. Never would give a statement to the cops.

What you want, in a self defense scenario, is something that does more than just give a man a belly ache and a surgery bill. Otherwise the threat is not neutralized and can continue to shoot at you.

Skribs
May 8, 2012, 12:41 PM
This is all interesting, but I think some of you are missing the point - if the bullet didn't penetrate deep enough to cause significant damage to the vitals, it doesn't matter if the bleeding is internal or external. The 12-18" penetration recommendation isn't to provide a through-and-through, it is to allow the bullets to sufficiently damage vital organs.

I was mostly referring to pistol rounds when I made the OP, although rifle rounds kinda got tagged with it (and I was thinking about the duplex load of #2 and #4 birdgshot). With a pistol round, even if most of the bleeding is internal, a deeper hole or a through-and-through will increase blood loss. It might not double it, but it will increase it.

As to rifles...if they dump their energy before reaching vitals and slow down to a velocity that will not result in a vast cavity, then the actual damage to the vitals is going to be very small. The large amount of damage done will be before it reaches the vitals. I'd rather have something that causes a medium-sized cavity and continues through than something that causes a large cavity but chokes too soon.

Remember, we're not just talking about how much energy is expended, but how it is expended and what it is doing with the energy after it is spent. It's not just how big of a hole, but where that hole is - both in shot placement and in the depth you penetrate to.

FIVETWOSEVEN
May 8, 2012, 12:45 PM
I thought that the requirement comes out of the possibility of shooting through an arm which takes a lot of the force out of the bullet impact when it reaches the vitals. Whenever I see a test to see if it penetrates 12"s, I rarely see a barrier but just the Gel itself.

Civilians are just as likely to have to penetrate barriers as LE in a shooting. A bullet may, or may not need to penetrate 12" to reach vital organs. It depends on the angle of the shot. Even then it has to completely penetrate vital organs, not just reach them.

No we aren't, we won't have to be shooting through car windshields or doors near the same as LE. Sure it could happen since I hear about people pointing their gun to a potential threat through the car door but when has that ever happened? Only case I remember reading was when a guy put a slug in his shotgun and shot a home invader that took cover behind his fridge or the many cases of people shooting through their bedroom door but that's it.

Remllez
May 8, 2012, 01:43 PM
I was always under the impression that hollow point ammunition was designed to cause more instant shock to the body using less shots thereby ending hostilities quicker without necessarily causing death, the theory being less individual wounds less chance of death.

Full metal jacket which relies more on blood loss rather than energy dump usually requires more shots to stop hostilities thereby increasing the likelihood of more internal damage and blood loss which in turn leads to more deaths.

The theory behind JHP was to incapacitate/injure rather than kill.
I may be wrong and please don't flame me too badly, but for some reason this theory seems to make sense to me. YMMV

allaroundhunter
May 8, 2012, 01:55 PM
I was always under the impression that hollow point ammunition was designed to cause more instant shock to the body using less shots thereby ending hostilities quicker without necessarily causing death, the theory being less individual wounds less chance of death.

Full metal jacket which relies more on blood loss rather than energy dump usually requires more shots to stop hostilities thereby increasing the likelihood of more internal damage and blood loss which in turn leads to more deaths.

The theory behind JHP was to incapacitate/injure rather than kill.
I may be wrong and please don't flame me too badly, but for some reason this theory seems to make sense to me

Let me try to correct some of this.

Hollow point ammunition was not designed to cause more instant shock. Handgun rounds are not traveling fast enough to deliver that kind of energy. They are designed to expand and cause a larger, (hopefully) more incapacitating wound than an FMJ round that is zipping through a body.

A JHP round is more lethal than an FMJ round, so the "less individual wounds less chance of death" is most certainly not true.

The theory behind JHP was to incapacitate/injure rather than kill
The theory behind the JHP is to expand to cause a larger wound tract and a larger loss of blood, not to attempt to save the life of its target. It is up to the shooter as to whether the shot will be incapacitating or not, and the shots that will incapacitate an attacker the fastest, also have a tendency to be the most lethal.

Sam1911
May 8, 2012, 01:58 PM
I was always under the impression

Not really. The lines between theory and practice get pretty blurry.

The primary factors are that hollow points are just another version of expanding/deforming bullet. When they strike something soft-ish they change from pointy needles to a big bull-dozer blade tearing through the tissue.

Instead of poking a little hole in something, they make a bigger, nastier hole in the target, grabbing tissue and tear it apart. There is no way that one can support an argument that a hollow-point is reasonably/realistically less likely to cause death than an FMJ.

The energy dump idea is probably highly over-rated, but what isn't over-rated is that the bullet's enegry is being used to a)deform the bullet itself, and b) act on more tissue because that bullet is getting bigger.

Like opening a drag chute or a sea-drogue, that very aerodynamically inefficient shape being forced through the medium does slow the projectile down quite a bit because that energy is being diverted into those other tasks.

One of the benefits, or simply "trade-offs" rather, is indeed lessened penetration, vs. FMJs.

FMJs can wound through a couple of means, like yaw and fragmentation if conditions are right. There isn't though a driving philosophical reason behind using them that says they're more likely to cause death. The only reason they are used -- at all -- is a historic (and flawed) belief in a kind of battlefield ethics that said that "civilized" (white) people shouldn't shoot each other with "inhumane" bullets designed to cause extra damage. :rolleyes: The idea is, of course, absurd, but there's more than a century of social momentum behind not arming our soldiers with the most lethal ammo they could have...so we don't.

Skribs
May 8, 2012, 01:59 PM
That sounds like political BS to me, Remllez. The goal of a hollowpoint is to cause more damage within the wound tract.

With a pistol, if you penetrate through-and-through, adding more power doesn't do anything. Making the bullet wider does. Compare the recoil and expanded size of a 9mm JHP with a .45 ACP and the 9mm wins on both counts. You're still counting on blood loss.

With rifles, the hollowpoint or yawing/fragmenting rounds dump energy better, creating a larger wound tract. Larger wound tract = more blood loss.

Anything saying hollowpoints are less lethal is just politics or marketing. Excepting underpenetrating loads, they are more lethal. Their purpose is to end the threat faster.

Loosedhorse
May 8, 2012, 04:49 PM
Energy which does not damage tissue is not meaningful.Well, that is a reasonable assumption. But it may not be true.

Just as many have taken to the assumption that 12 inches is the right "minimum" penetration, they have taken to the assumption that a handgun round with a large "energy dump" will not stop an attacker any better than a round penetrating the same amount with a small energy dump. But we don't know that.

Recall that the majority of assailants stopped by hangun fire don't die, and so were stopped by something other than a fatal wound. So, while we know that penetration of vital organs is needed for fatal stops, we do not know all the factors that influence the non-fatal stops (sometimes called "psychological stops") that apparently accout for most stops.Hence you can choose a bullet that penetrates 8” but if it hits along the periphery of the body it, too, may “over-penetrate”.That doesn't change the fact that a bullet that penetrates 18 inches in gel can be expected to overpenetrate more frequently (and with greater residual velocity) than a round that penetrates 11 or 12 inches.

Again, these days it's a bit of an anachronism, supposing we must choose between a low-energy dump round that penetrates 18 inches or more, and a high-energy dump round that penetrates only 8 inches. We can have both energy dump and penetration.

For example, there's the .40 S&W 125gr Barnes Tac-XP (http://www.shootingillustrated.com/index.php/9341/40-sw-doubletap-125-grain-barnes-tac-xp/), which can apparently be pushed to over 1400 fps and yet seems to still penetrate just shy of 18 inches in gel. And typical "bad ammunition" (like the infamous Hornady Critical Defense 9mm) actually penetrates 11 inches, just shy of "acceptable."

It's perhaps worth remembering, too, that the most common "bullet failure" in ammo tests is an HP that clogs with barrier material (like denim or gypsum), fails to expand, and then acts more like FMJ than an HP. So in use, the penetration of anything except the "latest and greatest" HPs may actually be greater than advertised (if clothing or other barrier is encountered).

TT
May 8, 2012, 04:50 PM
Brickeyee: It is called a free market.

Yup. Not everyone subscribes to the 12 minimum theory. And there are plenty of 12+ loads on the market for people who do, so what is the problem?

Skribs
May 8, 2012, 04:52 PM
The problem is twofold:

1) Most places nearby sell the fast, light, underpenetrating loads.
2) A lot of the newer bullet technology (such as attempts at making more reliable expanding bullets) are something I would purchase if they made a higher penetrating (15-18") load.

Remllez
May 8, 2012, 05:14 PM
I was merely offering an opposing viewpoint....I never said it was written in stone and it may be political BS. But I'm still not convinced it's totally false. Let's call it food for thought.....:)

Cosmoline
May 8, 2012, 09:16 PM
The 12-18" penetration recommendation isn't to provide a through-and-through, it is to allow the bullets to sufficiently damage vital organs.

I suspect the recommendation is sales spin, trying to turn a shortcoming into some asset. More is better when it comes to penetration.

Well, that is a reasonable assumption. But it may not be true.

How can energy which does not damage tissue have an effect? Are you suggesting that there's a psychological distinction between a round that stops mid-torso and one that exits? Or that the person shot can even tell?

Full metal jacket which relies more on blood loss rather than energy dump usually requires more shots to stop hostilities thereby increasing the likelihood of more internal damage and blood loss which in turn leads to more deaths.

They all rely on tissue damage. A round that doesn't damage tissue is a round that bounces off. And while that may sting a bit, it's not really going to stop someone at handgun energy levels. Even in the case of kevlar jackets, the round is still doing tissue damage by pressing into the tissue causing bruises or broken bones.

The energy itself isn't doing anything unless it damages tissue.

Of course there is a valid efficiency argument as well. If the handgun slug has 300 ft. lbs on impact, you want to use as much of that energy as possible damaging tissue. So it's true that the non-deforming fmj or hardcast that still has 100 ft lbs on the flip side hasn't used its power to maximum effect. The problem is there's so little energy to play around with when it comes to handgun bullets, as soon as you start making expanding tips there are risks the round will fail to do much of anything.

And I'd argue that giving you an exit hole is a nice bonus, so that's not really "wasted" energy.

Skribs
May 8, 2012, 09:27 PM
Cosmoline, the 12-18" isn't a sales pitch, it is what someone at the FBI concluded is needed for them to use as a standard when they select ammo.

How can energy which does not damage tissue have an effect? Are you suggesting that there's a psychological distinction between a round that stops mid-torso and one that exits? Or that the person shot can even tell?

It depends on how that energy is spent. In a pistol round, as has been said, amount of energy is one of those things you put into the story problem that doesn't get calculated into the equation. For a pistol, it is penetration depth and bullet diameter. If you "expend 100% energy", it means the bullet penetrated less. Any extra past the perp doesn't help, but any less before an exit wound does nothing. So, you're right, the extra energy does nothing once you overpenetrate. But that just means you erred on the side of more penetration, as opposed to having a bullet that did less damage.

On the other hand, with a rifle, a rifle does its damage through the energy dump. However, the bullet continues onwards after the energy dump and the large balloon-like cavity with minimal velocity and damages things behind it. If you go here (http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/index.htm#.223) and scroll up for the chart, you'll notice that most of the rifle hits are leaf-shaped. They have the big cavity up to about 20 or 30 cm, and then they have a shallow cavity for another 10.

What this means is that the round is causing damage with the energy dump up until 20-30 cm, and after that functions like a pistol round. The energy stops being a factor once the bullet slows down - after that it functions like a pistol bullet. In order to get the energy to matter all the way through the target, instead of having something that stops in the target, you would need something that maintains 2000 FPS through the exit wound.

allaroundhunter
May 8, 2012, 09:31 PM
If you "expend 100% energy", it means the bullet penetrated less. Any extra past the perp doesn't help, but any less before an exit wound does nothing.

Not completely true. Energy goes into helping the bullet to expand, and this means that that energy did not go into penetration.

Follow this thinking under ideal conditions:
Two bullets (identical in every way) are fired into a target.
One expends all of its energy and stops just short of exiting, while the other exits the target.
The first bullet will have expanded more and therefore caused a larger wound tract (though not significantly larger)

So, saying that a round stopping inside of a target does nothing more than a round that exits, does not hold true.

loose noose
May 8, 2012, 10:25 PM
Ya all might take a look at "Handgun Stopping Power" by Bob Campbell as he refers to Marshall's theories in regard to one shot kills. It is rather long but very interesting. You can find it on the internet, but I'm not sure where, as I copied it down about 5-6 years ago sorry.:o

Skribs
May 8, 2012, 11:52 PM
AAH, the problem is that what you're saying isn't what I'm talking about. It isn't two bullets, one designed to expand more and one designed to penetrate deeper. They both expand relatively the same, it's that the lighter bullet dumps the energy faster, resulting in a wider temporary wound channel, and the heavier bullet ploughs farther through. The temporary wound channel earns its name by snapping back into place. The reason it dumps more energy is because it has less sectional density.

It is true that the bullet uses the energy to expand, but it can only expand to a certain point. It dumps energy to expand, but it also dumps energy once expanded in the same way a parachute does.

Also, my OP was not about the difference between a bullet that almost exits and one that exits, but about one that meets or fails to meet the FBI minimum (usually 9.5-11.5" in ballistics gel for the 'uber elite defense' type loads) vs. one that is on the higher end of the FBI recommendation (I'm thinking 15-18").

Loosedhorse
May 9, 2012, 06:24 AM
How can energy which does not damage tissue have an effect? Are you suggesting that there's a psychological distinction between a round that stops mid-torso and one that exits? Or that the person shot can even tell? Well, there are several possible answers to your question.

One is that there may be something to the hydrostatic shock theory (http://en.wikipedia.org/wiki/Hydrostatic_shock) that has been advanced by Courtney and others.

The other is the larger kinetic impulse imparted to a body by a large energy dump bullet. Anyone who has shot a jug of water with slow hardball vs a fast JHP suspects that, yes, getting hit with one would be a different subjective experience than getting hit with the other.

Is that enough for fast JHPs with high, rapid energy transfer to cause more non-fatal stops than slower, lower energy transfer rounds? I can't know for sure without data; so I also can't know enough to discard the energy-dump theory, either, and accept the "only penetration matters" theory.

Agsalaska
May 9, 2012, 07:20 AM
I dont have anything to really add to this thread as I am by no means a ballistics expert. I tend to go with the most powerful load that I can comfortably shoot in all of my SD firearms.

Thumbs up to this thread though. Best discussion you will find on this topic on the internet.

loose noose
May 9, 2012, 10:13 AM
As a Police Officer I was involved directly in 4 shootings. Two were with .45 auto 230 grn hard ball ammo, and 2 were with Speer 185 grn. "shot glass" hp, from a .45 auto. The first one was a young male about 19 yrs. old who decided to ambush a couple PO's along with a few other young punks. In returning fire and heading for cover one of our rounds hit one of the perps in the hip and went thru and thru. (with the 230 grn hard ball) the perp ended up getting away and seeking medical assistance at a local hospital. The 2nd was an attack dog that had attacked a young boy while walking by the fence. My partner and I went out to investigate and sure enough the 120# German Shepherd came thru the fence went airborne toward the two of us. I instinctly fired hitting the dog in the center of the chest and he came crashing down just in front of us, however he got up and ran back into his yard and expired. Again using 230 grn hard ball ammo. The last two were with the 185 grn Speer Law Enforcement HP ammo, shaped like a shot glass. One was a young man who had just robbed a liquor store, and was running down an alley shooting back at yours truly one shot from my .45 hit the perp in the buttocks putting him down instantly. The 2nd was after a vehicle pursuit, that ended up in a TC and the perp managed to run, stopping briefly to take a shot at pursuing officers, ond shot from my auto using 185 grn struck him in the right inner arm stopped him immediately. Now that is why I carry 185 grn HP in my home defense weapon to this date.

Skribs
May 9, 2012, 10:54 AM
Noose, the load you're using was tested in a sub-compact and still went through 15". That is what I would consider a decent self defense load - an expanding round that has 15-18" worth.

Like I said, I'm not comparing "JHP to FMJ", I'm comparing "defense" loads that have 8-12" of penetration vs. loads that have 15-18".

Cosmoline
May 9, 2012, 01:44 PM
The other is the larger kinetic impulse imparted to a body by a large energy dump bullet. Anyone who has shot a jug of water with slow hardball vs a fast JHP suspects that, yes, getting hit with one would be a different subjective experience than getting hit with the other.

If we're talking about rifles or very powerful handguns, then I think we can all agree that the hydrostatic shockwave can be a major cause of tissue damage. But it's much less clear what role it plays with small, low powered handgun bullets. Milk jugs are a lot smaller than humans, and obviously made of different substances. So I'm skeptical how much can be learned from them. While humans are mostly water, our organs are also designed to be very flexible, and a wave that pushes them out of the way won't necessarily do any damage. If we expand we don't explode like plastic jug.

We do know that "energy transfer" in and of itself appears to play no role with medium and large game animals, unless you shoot them with something truly big enough to knock them down like an 8 bore. The handgun round, HP or FMJ, does not knock the body back or act like a prize fighter's punch. And we know that it's blood loss that stops the animal, or a CNS hit. The difference with humans is only mental. It's possible there's some difference in psychological reaction to a through-and-through wound and one which expands and stops. But I don't know of any serious study of it. So I remain skeptical of it.

460Kodiak
May 9, 2012, 06:58 PM
Using the same ammo for every situation and environment seems like wearing shorts year round, or snow shoes on a dry sidewalk in summer.

It just doesn't make a lot of sense. Use the right equipment at the right time. This applies to the ammo choice as well as the gun. Think about the possibilities before you load your gun and go out the door, and choose the appropriate ammo.

Loosedhorse
May 9, 2012, 07:05 PM
If we expand we don't explode like plastic jug.No, of course we don't. But even though a jug can explode, it does not explode with every bullet type.

As I said, the fact that it does explode with one type of bullet but not with another simply gives us an illustration of the higher magnitude of energy transferred in that short distance (the width of a water jug) with that bullet type. It suggests to me (but apparently not to you) that the subjective experiences of being hit with different bullet types would be different.

Not that the person hit would explode.our organs are also designed to be very flexibleDoes that mean our organs are "designed" to do well when exposed to a close-passing expanding bullet?

Putting aside the question of design, some organs are definitely not made to withstand the rapid stretching of a temoprary cavity: liver and spleen, for example. And large vessels, where their movement is restricted, are subjected to sheer forces by sudden stretch.We do know that "energy transfer" in and of itself appears to play no role with medium and large game animalsHow do we know that about energy transfer "in and of itself"? Is there some study of animal reactions to HP vs FMJ handgun rounds that you are referring to?But I don't know of any serious study of it. So I remain skeptical of it.I agree that there has been no definitive study. So, I think that means we should be skeptical equally of the theory that humans behave differently after being hit by a high-energy-deposition handgun bullet (compared to a low-energy deposition one) and of the theory that they don't.

MICHAEL T
May 10, 2012, 12:36 AM
Iam more worried about the ones that miss . Than under or over penetration

Cosmoline
May 10, 2012, 12:51 PM
How do we know that about energy transfer "in and of itself"? Is there some study of animal reactions to HP vs FMJ handgun rounds that you are referring to?

There's a great deal of field experimentation which has shown that a bullet that penetrates clear through generally kills more effectively than one which stops mid-way. And I don't know of any data suggesting that the raw energy--not the cavity and not the wound--has any ability to injure on its own.

If the handgun was throwing enough raw energy out the barrel to kill, then your hand would be shattered by the recoil, wouldn't it?

I think that means we should be skeptical equally of the theory that humans behave differently after being hit by a high-energy-deposition handgun bullet (compared to a low-energy deposition one) and of the theory that they don't.

I agree. And I'd say we should be universally wary of relying on expected human reactions to being shot. That's why my focus is on which round is going to cause the attacker to lose the most blood the quickest. It's blood loss that we *know* causes shock, and shock (true hypovolemic shock, not psychological shock) is the one thing other than a CNS hit which will cause that gun arm to drop and stop trying to kill you.

Skribs
May 10, 2012, 01:27 PM
LH, if the temporary cavitation caused by the bullet passing near an organ is below the elastic limit, it will not cause permanent damage. If it is above the elastic limit, it will cause damage. Different organs have different elastic limits, and there are other factors involved, but that is basically it. Our organs are elastic. If the bullet is strong enough, it will break them. If not, it wont.

t suggests to me (but apparently not to you) that the subjective experiences of being hit with different bullet types would be different.

It does suggest that the subjective experience is different with a higher energy bullet. However, I don't personally trust a subjective difference on someone who may be high on adrenaline and/or drugs.

Loosedhorse
May 10, 2012, 01:52 PM
There's a great deal of field experimentation which has shown that a bullet that penetrates clear through generally kills more effectively than one which stops mid-wayCan you cite any?

By the way, a comparison between bullets that stop midway and bullets that penetrate completely is not a test of the role of energy dump "in itself". A test of energy dump in itself would compare a low-energy-dump bullet that stopped half-way to a high-energy-dump bullet that stopped half-way; or compare a high-energy-dump bullet that penetrates completely to a low-energy-dump bullet that penetrates completely. That way, only the amount of energy dumped (and not also the penetration) is changed, allowing you to look at the isolated effect of energy dump--in itself.And I don't know of any data suggesting that the raw energy--not the cavity and not the wound--has any ability to injure on its own.Well, again: the energy of the bullet is what makes the wound in all cases: mostly by temporary cavitation with rifle velocities, and mostly with direct crush for handguns. And the question (for me) at handgun velocities is not so much if a round producing a larger temporary cavity contributes to wounding, but if it contributes to stopping an attack.If the handgun was throwing enough raw energy out the barrel to kill, then your hand would be shattered by the recoil, wouldn't it?Of course it wouldn't--as it obviously isn't.

You seem to have this very odd dichotomy--the bullet does the killing, not its raw energy. However, the bullet and its energy are inseparable as wounding agents: without energy, the bullet would be motionless.

The fact that the bullet has enough energy to wound, but the recoiling gun in your hand does not, is a simple matter of physics.and shock (true hypovolemic shock, not psychological shock) is the one thing other than a CNS hit which will cause that gun arm to drop and stop trying to kill you. No, there is at least one other element: the attacker deciding to stop can cause his gun arm to drop and stop trying to kill you. And so the question remains, does a high-energy-dump round increase the likelihood that an attacker stops (even without being killed)? Does such a round have no added effect? Does it make the attacker more likely to continue his attack?

I understand you have decided to ignore stops that don't involve loss of consciousness through catastrophic blood loss or CNS damage, but I'm not sure we should, especially as most attacks seem to be ened by the type of stops you're ignoring.However, I don't personally trust a subjective difference on someone who may be high on adrenaline and/or drugs. I still don't understand your point. As I said, these days, if you want a high-energy-dump round with good penetration, you can get it. It's not a question of "trusting" high-energy dump to do something, and therefore giving up good penetration; it's a question of whether you ignore the possible benefits of energy dump and focus solely on penetration.

It is true that with some low-energy rounds, if you choose energy dump you will end up with significantly low penetration. But even with .380 ACP, a good load (like the Buffalo Bore 80gr Barnes Tac-XP) can get you 11.5" of penetration. And remember, that if you want more penetration than that, you're giving up energy dump AND frontal area (of a less-expanding bullet).

Skribs
May 10, 2012, 02:37 PM
LH, that's the thing. The recommendation is 12" minimum. 11.5 doesn't even meet that.

Cosmoline
May 10, 2012, 02:58 PM
The fact that the bullet has enough energy to wound, but the recoiling gun in your hand does not, is a simple matter of physics.

It's the bullet that does the wounding. Yes obviously the energy permits the bullet to do this. But an equal amount of energy smacks right back into your hand. So obviously that energy--IN AND OF ITSELF--is not sufficient to do much of anything more than jolt your hand back a bit. It's the bullet's hole and to a lesser extent shockwave that do the work.

the attacker deciding to stop can cause his gun arm to drop and stop trying to kill you.

That's a fine end to any attack, but it can't be counted on. What's going on in the attacker's brain is simply not reliable enough for self defense against an imminent lethal threat. He might be stopped by strong language or a paintball, but he might not. What we KNOW will stop him is a CNS hit or sufficient blood loss to cause the blood pressure to drop fast enough that he can no longer shoot at you.

JohnBT
May 10, 2012, 03:25 PM
"Why do manufacturers make underpenetrating loads for defense?"

Maybe they figure you only need to shoot the skinny people because you can outrun the fat ones. ;)

Loosedhorse
May 10, 2012, 03:39 PM
LH, that's the thing. The recommendation is 12" minimum. 11.5 doesn't even meet that. Right. So either:

Realize the recommendations is arbitrary, designed for the FBI, and gives you no guarantee that a penetration of 12.5" will work but 11.5" won't. In fact, we don't even have data saying that a round that is rated for 12.5 inches of gel penetration is any more effective than one rated for 11.5".

Or move up to something better than .380, so you can get penetration beyond 12 inches AND good energy transfer.

Or, of course, stick with .380, pretend we know that energy transfer does nothing, and so ignore it--and choose a less expanding, deeper penetrating round (and assume that expansion is less important than penetration).But an equal amount of energy smacks right back into your hand.Nope. You are wrong on the physics. You could look it up. The bullet in flight has far more energy than the gun in recoil.That's a fine end to any attack, but it can't be counted on.I'm not saying to count on it only. But I think you're saying that you have decided to depend on penetration only.

I'm saying, we don't know that energy dump does nothing to end attacks--so why not choose a round that will give you a high energy transfer AND good penetration; choose both. As I said, these days, you don't have to choose just one.

Skribs
May 10, 2012, 05:55 PM
We dont have data and never will (without a virtual reality simulation), but I'm looking at why they made that choice. It was because that is the amount they believe necessary to reliably hit vitals is 12-18". I'm not saying that a 12.5 will be much better than an 11.5. I am saying that a 15-18 will be better than either. Beyond that, I don't see much benefit. You could go the other direction, too, and say "what about an 11? it's close enough." Keep doing that and you're down to 3 inches, because it's close enough to 3.5. You have to draw the line somewhere.

JohnBT, I literally lol'd.

Loosedhorse
May 11, 2012, 07:41 AM
We dont have data and never will (without a virtual reality simulation)Virtual reality would not be data.

I disagree about "never will". There are (unfortunately) a lot of shootings by LEOs and private citizens to stop attacks. There is no concerted effort to collect that data to look at what effect different bullets are having (beyond LE depts looking internally at their own shootings, to see if their issued ammo is performing "up to expectations"--and it sometimes is not, despite being "gel-approved"). So there is plenty of data out there...that is not being gathered.

Collecting it would take money and effort. Given the flames that met the Marshall-Sanow data, I suspect that any new effort would have to be led by federal dollars, not private effort (unfortunately, as a private effort would have a lot of advantages).

Recall that nothing like the FBI's current gel-and-barrier protocols existed before the 1986 Miami Shootout was "blamed" on one 9mm Silvertip bullet. So, I guess we'll have to wait for the next "ammo failure" as the next motivation for them to look at a different theory.

In the meantime, some will consider other theories than the FBI's "all that matters is 12-18" penetration" theory, even if the gov't doesn't think we should. And apparently, some ammo companies are fine with that.

Free market.

brickeyee
May 11, 2012, 12:51 PM
But an equal amount of energy smacks right back into your hand.

This is simply wrong.

Momentum is conserved.

The momentum of the bullet and everything else exiting the barrel imparts the same momentum to the gun & shooter.

NOT ENERGY. MOMENTUM.

Shawn Dodson
May 11, 2012, 12:54 PM
The purpose of adequate penetration is to make sure the bullet can reach and damage vitals critical to immediate survival.

Well-designed expanding bullets consistently penetrate between 14-16 inches, in both bare gelatin and gelatin covered by four layers of heavy denim cloth. 14-16 inches is the "sweet spot" for expanding bullets designed to reliably penetrate a minimum of 12 inches.

6.1.2 [bare gelatin] Most physicians knowledgeable in wound trauma believe that adequate penetration depth is the most important single property in handgun ammunition. The appropriate value for minimum penetration depth has generally been assumed to be 12 inches ever since the first FBI wound ballistics meeting in 1987. Unfortunately, this assumption has often been interpreted very simplistically (i.e., 12.1 Inches of penetration is good, but 11.9 inches of penetration is no good), but the real situation is more complicated. The problem is the possibility that the bullet will require an unusually large penetration to reach vital structures well inside the body. This can occur when the bullet must traverse non-critical tissue; e.g., the extended arm of an assailant aiming his handgun, and/or an unusual bullet path angle in the torso, and/or an unusually fat or beefy individual. The probability of needing this extra penetration is a judgment call, but most people believe it is a significant factor and much more important than the relatively modest increase in expanded diameter achieved by reducing penetration depth (e.g., approximately 30% increase in expanded bullet diameter is achieved by designing to an 8 inch penetration depth rather than 12 inches). This is the reason the professional wound ballistics community specified the 12 inch minimum penetration even though they are well aware that an 8 inch penetration is usually adequate. The suggested specification values for mean penetration depth are greater than 12.5 inches and less than 14.0 inches. Even at the limit of minimum value of this range (12.5 inches) and the limiting value of standard deviation (0.6) in Section 6.1.1, about 80% of the penetration will be greater than 12 inches and essentially all will be greater than 11 inches. This bare gelatin test provides a lower limit on penetration because most shootings will involve at least some clothing; slightly less expansion and slightly deeper penetration can be expected in typical service use.

6.2.2 [denim covered gelatin] The mean penetration depth in this section can be expected to be somewhat larger than in Section 6.1.2 (bare gelatin), and represents a reasonable upper bound on the mean penetration depth in service. The suggested specification values for mean penetration depth are greater than 13.0 inches and less than 16.0 inches. The realities of JHP bullet performance eliminate any practical concern that penetration depth will be inadequate in this test for any ammunition with adequate penetration in the Section 6.1 test. A one inch increase in maximum penetration depth corresponds to approximately a 0.02 inch reduction in expanded diameter, which is not a significant concern as long as the requirement of Section 6.2.1 is met. The general discussion of penetration depth in Section 6.1.2 also applies here.

-- http://www.firearmstactical.com/iwba.htm#Specification%20Supplement

Skribs
May 11, 2012, 01:18 PM
Virtual reality would not be data.

I disagree about "never will". There are (unfortunately) a lot of shootings by LEOs and private citizens to stop attacks. There is no concerted effort to collect that data to look at what effect different bullets are having (beyond LE depts looking internally at their own shootings, to see if their issued ammo is performing "up to expectations"--and it sometimes is not, despite being "gel-approved"). So there is plenty of data out there...that is not being gathered.

There are a lot of "studies" but they have all been vetted as not providing accurate data because of the factors involved. A virtual reality program, which accurately simulates physics and human anatomy and has millions of iterations run from various angles, would more accurately provide us with information on how reliable different bullets are at causing an involuntary stop assuming a "hit". There are obviously factors that would need to be defined that I'm not going to go into.

Recall that nothing like the FBI's current gel-and-barrier protocols existed before the 1986 Miami Shootout was "blamed" on one 9mm Silvertip bullet. So, I guess we'll have to wait for the next "ammo failure" as the next motivation for them to look at a different theory.

In the meantime, some will consider other theories than the FBI's "all that matters is 12-18" penetration" theory, even if the gov't doesn't think we should. And apparently, some ammo companies are fine with that.

The FBI isn't saying that all that matters is 12-18". They are saying that 12-18" is what should be expected to reliably hit vital organs. Whether you believe the bullet should exit or stay, there is no denying the fact that if the bullet fails to penetrate deep enough, it will not hit vitals, and will cause significantly less trauma than if it had.

Loosedhorse
May 11, 2012, 02:04 PM
A virtual reality program, which accurately simulates physics and human anatomy...Would be based on one assumption after another: if a "simulated" blood vessel is nicked, how long until the "modeled" person is incapacitated? If the model receives a huge energy dump bullet that hits nothing major, do we "decide" he continues as if unwounded, or is slowed down 20%, or that he immediately stops? Or can any of those happen, based on a randomized result--and if so, what probabilities do we assign to each of the possible responses?

If it helps, this "modeling" was already done by the NIJ/LEAA using their (in)famous "Computer Man" 3D model. Their model resulted in the "best load" being designated as 95 gr .38 Spc+P, with a Relative Incapacitation Index of 28.9. As a reference, .45 harball was 4.3.

And the evil 9mm Silvertip was 27.5. So, it may be fairly said that the RII influenced the ammo selected by the FBI and used for the Miami Shoot-Out. Who knows what mistakes the new model will make, based on the assumptions fed into it. Same-ol', same-ol': GIGO.

The only way to discover if our model and assumptions are valid would be to compare their predictions to actual data from shootings. That is the heart of scientific theory testing by experiment.The FBI isn't saying that all that matters is 12-18".It assigns some smaller importance to bullet diameter, but does NOT designate a "minimum acceptable" diameter (other than designating what calibers it will issue), so, I wouldn't consider that a requirement in the same sense. If there are any other designated requirements for ammo other than their minimal penetration depth requirement, please tell me what those are.

BTW, that 18 inch figure is not a maximum, with penetrations beyond that disqualifying ammo. It is a "maximum desirable (http://www.zoklet.net/totse/en/bad_ideas/guns_and_weapons/10mmpist.html)": "It should be noted that no maximum penetration standard was established." there is no denying the fact that if the bullet fails to penetrate deep enough, it will not hit vitals, and will cause significantly less trauma than if it had.This statement is a truism, but it is unhelpful because it does not define "deep enough." It also assumes trauma to the vital structures is the only way to effect a stop.

huntsman
May 11, 2012, 02:17 PM
The problem is the possibility that the bullet will require an unusually large penetration to reach vital structures well inside the body. This can occur when the bullet must traverse non-critical tissue; e.g., the extended arm of an assailant aiming his handgun, and/or an unusual bullet path angle in the torso, and/or an unusually fat or beefy individual. The probability of needing this extra penetration is a judgment call, but most people believe it is a significant factor and much more important than the relatively modest increase in expanded diameter achieved by reducing penetration depth (e.g., approximately 30% increase in expanded bullet diameter is achieved by designing to an 8 inch penetration depth rather than 12 inches).

Any plans to redo these studies but factor in now that people are bigger? (That’s the finding of the latest Gallup-Healthways Well-Being Index, which shows that 63.1% of adults in the U.S. were either overweight or obese in 2009)

I'm thinking 12" won't cut it maybe 20" will, how about shooting those fancy SDHP into something the consistency of 8" of fat?

bottom line hit the vitals forget about what the bullet may do after that.

Loosedhorse
May 11, 2012, 02:39 PM
bottom line hit the vitals forget about what the bullet may do after that.Good advice, but...

Which brand of ammo always hits the vitals, again? I'll make sure to buy that one! ;):D

Even if we don't want to, we may in a gunfight find out that outcome hangs on what the bullet does to the attacker when it doesn't manage to hit the vitals. Which is why I am puzzled that there seems to be so little interest in looking at that.

huntsman
May 11, 2012, 04:32 PM
a miss of the vitals is still a miss eventhough it is a GSW ;) is an expanding bullet enough to compensate for a miss? or false hope that might bite you in the butt?

Skribs
May 11, 2012, 04:55 PM
A hit centered on the vitals that doesn't penetrate deep enough will not hit the vitals. "Placement is everything" is a myth as far as I'm concerned. Placement is only half of causing enough damage, the other half is having enough penetration to cause damage to something that matters.

Huntsman, I'm not hoping an expanding bullet will compensate for a miss. I am hoping that it will cause a larger hole and nick the artery that a non-expanding bullet would have slipped by.

Loosedhorse
May 11, 2012, 05:16 PM
false hope that might bite you in the butt?The idea that any shot you fire--or any shot that hits--will actually end the fight might also be a false hope.

It's interesting: it seems to me that in order to criticize me for considering anything but penetration, you have to say that I'm depending on it.a miss of the vitals is still a missHmm. Somebody better tell IPSC and IDPA that. For some reason, both organizations give you some credit for hitting anywhere on the target--they don't give you a zero if you "miss the vitals"--you get at least some points for every bullet that hits.

Real gunfights seem like that, too. Sometimes you don't hit anything vital, but the attack stops immediately; sometimes you hit something vital, but the attack goes on for long enough to kill you.A hit centered on the vitals...The importance of penetration ASSUMES this, doesn't it--that you actually scored a hit "centered" on a vital organ. If you didn't, all the penetration in the world, according to the only-penetration-matters theory, won't help--you'll get no effect.

If bullets actually do at times---and we know it's most times--stop fights without hitting anything vital, that might be important, since precise aiming in the fading or absent light and the moving-target-moving-shooter reality of a typical gunfight will be dicey. That will make your needed A-Zone hit a hard thing to depend on--and you must depend on it, if the penetration-only theory is right.

Skribs
May 11, 2012, 07:05 PM
LH, there are two types of stops - voluntary and involuntary. Voluntary is largely irrespective of the bullet used (and often whether you even hit) and is more based on the fact that there is a gun and it was shot. I cannot control the majority of the factors that cause a voluntary stop, as they are with the other person.

What I can control is the factors that allow the bullet to excel at causing an involuntary stop. With a handgun it becomes a lot harder, but some of those factors are placement, penetration, and follow-up shots. If I miss the vitals, it's not going to be as effective. If I don't penetrate deep enough to hit the vitals, it's not going to be effective. And if I can't get fast follow-up shots (for the inevitable misses, multiple assailants, and shots that zip through without causing enough trauma to stop the attacker in his tracks), then I'm pretty much useless after all of these shots.

There are more than one factor that's important. I'm specifically looking at one factor here - penetration. That doesn't mean placement isn't important. It means that if I look at two bullets, both which offer reasonable recoil and accurate placement, then I would like to look at penetration.

I understand why whenever someone asks "what's the best caliber" or "should I use JHP or FMJ", a lot of people say "shot placement." I know shot placement is important, but that doesn't answer my question.

Loosedhorse
May 11, 2012, 08:05 PM
Voluntary is largely irrespective of the bullet used (and often whether you even hit)Sounds like you're making another assumption. I've said many times that we don't know whether energy dump--which is influenced by the type and weight of bullet used--changes the probablity of a "voluntary stop"; but you seem to claim you know it does not.

Getting back to your question. We've said already that the main reason that manufacturers produce the loads they do is that people buy them. My guess is that one reason that people buy them is that, despite the dire warnings of the FBI, our graveyards are not lined with markers carrying the epitaph, "He shoulda used a load that penetrated closer to 18 inches in gel."

;):D

As I said before, without data, there is no scientific way to choose among competing theories. There's just opinion and choice. And so, the market lets us choose.

loose noose
May 11, 2012, 08:16 PM
Changing the subject just a tad, when and if you get involved in a shooting, you best tell the court that you simply shot to stop the aggressor, not kill him if that's what happened. Not why you chose such a bullet based on what you read or assumed was factual.

huntsman
May 11, 2012, 08:48 PM
A hit centered on the vitals that doesn't penetrate deep enough will not hit the vitals.

Yep penetration should be #1 so why risk it with a bullet that could clog up or worse yet fragment, shot placement while not a given can at least be worked on with training but bullet failure won't be evident until it's too late.

I bet it'll really suck to hit COM but only to have a HP stopped by Carhartt and a Hoodie and 6" of fat

Skribs
May 11, 2012, 09:08 PM
LN, I have said several times that my goal is to pick a load that will stop the attack as quickly as possible. If I go to court, I'm not going to be defending my choice of load (my lawyer will be), I am going to be explaining why I had just cause for self defense.

Huntsman, hollowpoints that clog up actually penetrate MORE because they don't expand and thus don't expend the energy. See the AR15.net ammo FAQ (linked on page 2 of this thread) for a photo of gel reports after drywall - the pistol bullets clogged up and overpenetrated a lot. At that point, they function much like a FMJ.

Loosedhorse
May 11, 2012, 09:55 PM
Not why you chose such a bullet based on what you read or assumed was factual.A bit off subject, as you say. But I plan to be able to explain all my choices: the gun I chose, the ammo I chose, why I was carrying at that time and in that place, and why I had no choice but to shoot to stop (as you reminded us).

NDhawg
November 2, 2012, 01:47 PM
Mass x Velocity = Energy

Energy expended in the target results in damage

Energy that continues outside the target is useless

Wound Cavitation is the damage done to tissue surrounding the wound channel from the release of energy from the bullet

Tissue damage (wound cavitation) is what stops a threat, particularly if it is nervous tissue

An ideal SD round will expend all of it's energy within the target. This means that if a bullet passes through the target there is wasted energy. You will rarely be shooting through barriers for personal defense and you will also need to worry about an over-penetrating bullet passing through walls etc. in populated areas.

This is why fast light bullets that have high energy values due to velocity often do not do near the real world damage as slow and heavy bullets. Think .45 ACP vs. 9mm

brickeyee
November 2, 2012, 04:30 PM
Mass x Velocity = Energy

Simply wrong.

Mass x velocity = momentum

Energy is mass times velocity squared divided by 2.

Energy = (mv^2)/2

And do not forget that grains are NOT mass, they are weight.

You have to divide by g (acceleration of gravity, 32 ft/s^2) to get mass.

Skribs
November 2, 2012, 05:06 PM
Wound Cavitation is the damage done to tissue surrounding the wound channel from the release of energy from the bullet

There's a permanent and temporary wound channel. The energy expanded by a pistol bullet is not sufficient to cause permanent damage. The tissue just snaps back into place. How most pistol rounds deal damage (read: excepting magnum bullets shot out of rifles or the microcaliber PDW rounds like 5.7x28mm) is simply by crushing tissue beneath them, which means the energy itself is less important than the design of the bullet. In this case, what matters is expanded diameter and penetration depth.

You also bring up tissue damage. Tissue damage itself helps, but it's specifically what you damage that affects incapacitation. If the bullet stops before reaching vital organs, it will fail to damage the vital tissue, and thus fail at causing a physiological stop. That is why the FBI reccomends 12-18" minimum penetration; so when you're shooting that guy through the arm at an odd angle, the bullet is still capable of reaching the heart.

Also, holy necro first post batman!

EvilGenius
November 2, 2012, 05:26 PM
I think a lot of folks would find this video interesting. (Warning: graphic medical images)

http://www.youtube.com/watch?v=tku8YI68-JA&list=FLdHkVjhMVf7HXRa-jRmDGaA&index=4&feature=plpp_video

What I take from this is:

1) Penetration on vital organs is key.

2) Most handgun rounds do not penetrate well.

3) Size of holes left behind is more important than energy transfer in handguns. (The bigger the hole, the more effective the round is, but it's up you to decide if you want fewer bigger holes or more smaller ones, I.E. 9mm vs .45)

4) Energy transfer in a handgun round is a joke. (9mm = 10 lb weight dropped from .75")

5) Even a .223 or .30 cal rifle round will only make a hole that size unless it tumbles. (It has to encounter a lot of tissue to start tumbling.)

6) 12" of penetration on ballistics gel does not = 12" on a human body.

etc.

holdencm9
November 2, 2012, 10:52 PM
I will echo that I do think the 12" recommendation is a bit arbitrary, for LEO, and I don't worry if my pocket pistol ammo stops at 11" in the gelatin tests. It doesn't under-penetrate, it just penetrates less than my 9mm or .45, but it is a balance of pocketability and power. Of course whenever possible I carry more firepower, but don't feel undergunned with my .380. There is no magical line of death that if the bullet reaches, you die. In the end it is just a balance of the size of gun, cartridge, amount of expansion, and penetration. I don't think Speer should have to test their .32 or .380 ammo and if it fails to meet some arbitrary line they pull it off the shelves. I also don't think they are misleading consumers by marketing a round as self-defense if it only penetrates 10 inches.

Additionally, I know this wasn't meant to be a FMJ vs JHP thread, but that is often what it boils down to. That, or JHP #1 expands less, but penetrates more than JHP #2. I like to think of it from a perspective of potential scenarios and advantages of each.

1. You miss. Advantage neither (or maybe JHP that may have less chance of ricochet).
2. You miss COM entirely and hit soft tissue in a non-(immediately)-life-threatening body part. Either way you get a through-shot. Advantage JHP, since chances are, it will hurt more, (think psychological stop), leave a bigger exit hole, and have less velocity on the other side to hopefully do less damage.
3. You hit COM, adequate penetration, but just barely miss a vital like the heart. Advantage JHP because it will hurt more, leave a bigger wound channel, and the expanded diameter may knick an artery or something important.
4. You hit COM, perfect trajectory for a heart-hit, but since you had to shoot through a wall or door, the JHP expanded and did not penetrate enough, but the FMJ did penetrate enough and hit the vital. Advantage: FMJ.
5. You hit COM, perfect trajectory for a vital-hit, and you did not have to shoot through anything, so both JHP and FMJ work fine. Advantage: neither.

As you can see, only one scenario favors the FMJ. People get so caught up in the idea that they will have to shoot through something, and assume the most likely scenario is the bullet stops 1" short of the heart, they never worry about the other, more likely, scenarios.

Again, it all comes to balancing the variables and finding something you are comfortable with. Is a round that expands to 0.45" and penetrates 12.5" fine, and a round that expands to 0.6" and penetrates 11.5" is insufficient? I don't think so. Or what about a .355" round that doesn't expand at all and penetrates 16"? that's for everyone to decide for themselves.

captain awesome
November 3, 2012, 12:55 AM
Guess we are dredging this up again? LOVE first posters.

To all of you "bullets that pass all the way through are wasted energy" believers;
CODSWALLOP.

Take any two bullets, that are of the same diameter and weight. Assume They expand to the same diameter when entering the tissue at the same place in the tissue, and the projectiles retain the same wait. One is moving fast enough to make it through the "target" the other is not. The faster round will almost always be more effective. (there is an exception to this which is why I use the word "almost", I have read about a velocity threshhold where hard cast bullets with large meplats do less damage than the same bullet going slower which is negated by turning them into hollow points, but that is another subject all together)

Here's why, and you don't need energy and mass formulas to prove it, just common sense. The answer is partially Hydrostatic shock. The faster a bullet is moving, the more Hydrostatic shock it will deliver. The faster projectile will move the flesh around it at a higher velocity, which means it will move the flesh more. That means the temporary wound channel will be larger, and the permanent wound channel as well, as the energy rips the flesh.
Consider a rock falling into water. It will splash. Now Double the velocity of the rock and do it again. It will make a larger splash. The same can be seen with meteorites striking the earth. Take two rocks of the same size, drop one from your roof and the other from space. Which one makes a bigger crater or causes more damage? And last comparison; If you have ever seen a 7.62x39 hitting water jugs, and a 308 hitting the same water jugs, the difference in the resulting water works is well, the 308 is quite spectacular, the 7.62x39, is not so much.
Penetration really has nothing to do with this aspect of the argument, but is certainly an added bonus. If that bullet is moving farther into the target, more of the target will be damaged, plain and simple.
If someone is worried about hitting bystanders, so be it, it's a valid concern to be sure. Don't think that having it stop in the flesh makes it more effective, that is foolish.

Skribs
November 3, 2012, 02:17 AM
4. You hit COM, perfect trajectory for a heart-hit, but since you had to shoot through a wall or door, the JHP expanded and did not penetrate enough, but the FMJ did penetrate enough and hit the vital. Advantage: FMJ.

Actually, after shooting through drywall, the JHP will clog up but fail to expand (hydraulic pressure is usually what drives the expansion). Hence, it will be clogged up, won't expand in the human target, and act like a FMJ zipping through.

The 12" penetration recommendation wasn't based on barrier penetration, but rather on hitting the target at an odd angle and/or through the target's limbs.

Oh, it WAS a JHP #1 vs. JHP #2 thread.

5) Even a .223 or .30 cal rifle round will only make a hole that size unless it tumbles. (It has to encounter a lot of tissue to start tumbling.)

Depends on the design of the bullet. Some yaw fast, some yaw slow, some yaw at a random point.

There is no magical line of death that if the bullet reaches, you die. No, but in a situation where one bullet stopped short of vitals...you see where I'm going with this.

Captain Awesome, if you have two bullets that are exactly the same except one penetrates deeper, that one is going to require more energy, which means greater recoil. However, I think that it is worth it to get the round deep enough.

Harley Rider 55
November 3, 2012, 06:16 AM
Liability - there's a personal injury attorney on every corner.

beatledog7
November 3, 2012, 08:25 AM
The original question: Why do manufacturers make underpenetrating loads for defense?

The answer is the same no matter about what thing you ask it: they make it because they discovered it was profitable to make and sell.

If an ammo/bullet maker believed he could make a profit selling rounds consisting of worn-out brass and pre-chewed Juicy Fruit, he would do it, and why not? All the discussion of the science behind various aspects of bullet design, velocities, etc. is interesting to a point, but it overreaches the actual question.

Why does the hotdog vendor sell hotdogs? It's not for health reasons, and it's not for nostalgia; it's because he can buy, heat, and present a hotdog at a cost of .23 and sell it for 1.75, and he needs no other reason.

k_dawg
November 3, 2012, 10:39 AM
I wish the only concern innocents in a shooting was overpenetration.

Invariably, they are hit by flying bullets that never hit the perp in the first place.

benEzra
November 3, 2012, 10:56 AM
I think security applications in heavily populated areas (such as a casino, mall, travel terminal) have different factors from the home defense or personal defense scenario. If I was in the situation where I knew there would be hundreds of bystanders, I would want something that stops inside the assailant.
In my current house, any round that exited an assailant in my hallway and that was capable of penetrating an exterior wall would travel about 25 yards and enter a mobile home next door. So, no, I most assuredly do NOT want a HD round that will penetrate 18" in gelatin, and I avoid them. If you prefer very deep penetration, that's your choice, and there are plenty of loads on the market that meet your criteria. I'm glad there are also loads on the market that meet mine; that is the beauty of a free market, after all.

bassdogs
November 3, 2012, 08:26 PM
Think the short answer is that some of us are not zombie hunting milita guys who like to believe they are preparing for a full scale military assault on their humble home. Like others have said on the thread, don't like them, then don't buy them. Those of us who have decided that we aren't wanting a round to penetrate thru 3 walls and lodge in the back seat of our neighbors car that is sitting in his garage, don't think we are making a compromise when we purchase reduced recoil rounds or select a HD weapon in a caliber that likely won't exit a bad guy.

The FBI really gave a lot of gun guys a good handle to use to smear certain weapons and ammo. All this use to be limited to not relying on a 25auto or 32S&W that are famous for being anemic. Then it was the 38 and the 380. Amazingly the 38 and 380 are making a comeback.

holdencm9
November 4, 2012, 12:59 PM
Actually, after shooting through drywall, the JHP will clog up but fail to expand (hydraulic pressure is usually what drives the expansion). Hence, it will be clogged up, won't expand in the human target, and act like a FMJ zipping through.

Never specified type of wall. It could be a car door, glass, anything. My only point was it loses some steam on its way to the target. But you did just make my point for me that, if the JHP doesn't expand, it is effectively an FMJ. So that negates some of the FMJ's advantage.

No, but in a situation where one bullet stopped short of vitals...you see where I'm going with this.

I hear ya, and it is always a concern. Whenever possible I carry a bigger better cartridge, but sometimes I may be carrying something in the gray area of less penetration. Again, not "under-penetration." I just don't get why the "stop short" concern is always at the forefront, when, as I showed, there are a lot of other possibilities. IMO it is actually way more likely that you will miss a vital than have a bullet on an otherwise-perfect trajectory stop short. In many instances, for many people, a lighter-recoiling round with greater expansion and less penetration may be better for someone.

The Miami shooting is one very infamous instance where allegedly a bullet stopped about an inch short, and if only they had used a more powerful round, the perp would have been stopped much sooner, avoiding more tragic loss of life. But, of all the lessons we can take away from that shootout, I think "such and such round or x-inches penetration is inadequate" is the least important. Shot placement, tactical/situational awareness, sustained suppressive fire, and not bringing pistols to a rifle fight, I think are all much more important lessons.

allaroundhunter
November 4, 2012, 08:52 PM
5) Even a .223 or .30 cal rifle round will only make a hole that size unless it tumbles. (It has to encounter a lot of tissue to start tumbling.)

No, it does not have to encounter a lot of tissue to start tumbling; all that is required is to destabilize the bullet. The action that causes this is the change in density from air to human tissue. When a .223 round hits human tissue at self defense ranges, it will be traveling over 2,700 fps.

The center of mass of the bullet will be slightly behind its longitudinal center, and this means that the front of the bullet is lighter. When the round impacts human tissue, the immediate change in density will cause the bullet to slow and because the front of the bullet will slow at a faster rate because. This is what causes yawing, the rear of the bullet will end up going faster than the front and will "tumble" end over end once this destabilization occurs.

EvilGenius
November 4, 2012, 09:33 PM
No, it does not have to encounter a lot of tissue to start tumbling; all that is required is to destabilize the bullet. The action that causes this is the change in density from air to human tissue. When a .223 round hits human tissue at self defense ranges, it will be traveling over 2,700 fps.

The center of mass of the bullet will be slightly behind its longitudinal center, and this means that the front of the bullet is lighter. When the round impacts human tissue, the immediate change in density will cause the bullet to slow and because the front of the bullet will slow at a faster rate because. This is what causes yawing, the rear of the bullet will end up going faster than the front and will "tumble" end over end once this destabilization occurs.
Go watch the video.

By the time it starts to destabilize and yaw it's usually already on it's way out the back of a human sized torso.

Unless you've got specialized ammo designed to destabilize earlier than a normal FMJ. Which is plenty available.

Where the horrid injuries that result from tumbling come from is entries at odd angles that send the bullet through a longer path through the body. Like if someone was prone and took a round through the shoulder or upper chest/back and heading towards the groin. They would suffer much greater injuries than someone who got hit dead square standing upright.

allaroundhunter
November 4, 2012, 09:49 PM
It isn't a video matter, it is a matter of physics.

The immediate density change is what causes the destabilization, even if the bullet does not begin to tumble until the back of the torso.

Warp
November 4, 2012, 10:01 PM
Yep penetration should be #1 so why risk it with a bullet that could clog up or worse yet fragment, shot placement while not a given can at least be worked on with training but bullet failure won't be evident until it's too late.

I bet it'll really suck to hit COM but only to have a HP stopped by Carhartt and a Hoodie and 6" of fat

FYI: When hollow points clog and fail to expand it leads to an INCREASE in penetration. Not a decrease.

I'm not sure where you are getting your misinformation.

EvilGenius
November 4, 2012, 10:39 PM
It isn't a video matter, it is a matter of physics.

The immediate density change is what causes the destabilization, even if the bullet does not begin to tumble until the back of the torso.

I wasn't arguing that it didn't, just that it doesn't happen with in a couple of inches like people think.

A lot of center mass square hits result in an exit hole not much larger than the bullet dia. because the average torso isn't thick enough to suffer from the effects of tumbling ( because by the time it starts to tumble it's already leaving) unless it's hit at an extreme angle.

Warp
November 4, 2012, 10:47 PM
No, it does not have to encounter a lot of tissue to start tumbling; all that is required is to destabilize the bullet. The action that causes this is the change in density from air to human tissue. When a .223 round hits human tissue at self defense ranges, it will be traveling over 2,700 fps.

The center of mass of the bullet will be slightly behind its longitudinal center, and this means that the front of the bullet is lighter. When the round impacts human tissue, the immediate change in density will cause the bullet to slow and because the front of the bullet will slow at a faster rate because. This is what causes yawing, the rear of the bullet will end up going faster than the front and will "tumble" end over end once this destabilization occurs.

With M193 and M855 this does not happen as reliably as users would like.

allaroundhunter
November 4, 2012, 11:12 PM
With M193 and M855 this does not happen as reliably as users would like.

No they don't, especially the M855 with its steel core. The predecessor to the M855 and M193 rounds yawed much more reliably and much earlier than the modern rounds. If one is dead-set on using FMJ for defense out of a rifle, a round with a track record for being easily upset and destabilized is the best choice.

Warp
November 4, 2012, 11:17 PM
No they don't, especially the M855 with its steel core. The predecessor to the M855 and M193 rounds yawed much more reliably and much earlier than the modern rounds. If one is dead-set on using FMJ for defense out of a rifle, a round with a track record for being easily upset and destabilized is the best choice.

What round(s) would this be, and where can they be purchased?

Just curious, I've decided on defensive .223/5.56 already for myself

allaroundhunter
November 4, 2012, 11:34 PM
Personally, I wouldn't recommend them for anyone , and I actually haven't seen any recently. The rounds that I have seen that did this best were actually old rounds that my grandfather had bought close to 20 years ago. All I remember is that they were light rounds (I think 52 gr?), but they might have been 55 gr...

I don't remember the designation for these rounds, but hopefully someone with a better memory or knowledge base than myself will come along :o

-v-
November 5, 2012, 01:28 AM
We all do remember that penetrating the human skin is roughly equivalent to penetrating 4" of ballistics gel as was observed by Dr. Fackler? So a 12" in gel penetration is equivalent to 8" of penetration after penetrating the skin on a frontal shot, and probably less if you have a round that hits an arm before striking COM.

Most sensible comment so far is aim for COM and vitals, and shoot as many times as it takes for the threat to stop. If they stop, sit down and contemplate the life choices they made to this point. Excellent! Threat stopped. If they stop, collapse, and create mess to clean up later. Excellent! The threat is stopped.

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