A gel expert explains
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And that is why this—
—is still self-contradictory and still makes no sense at all.
No one has claimed otherwise—
—and it has nothing to do with supporting the prior claim that you made that, "...it is precisely because of the lack of such direct correlation that I consider overall disruption by a bullet in a gel very meaningful."
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Actually, it was and is by many as far as penetration and expansion is concerned. FBI standard of 12-18" penetration in soft tissue has been accepted by many to be equivalent to 12-18" penetration in 10% standard gel.
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Ah, I see. Your tests?
And in which peer-reviewed professional/technical journal may we see the research and test data that provides confirmation of your claim of "better correlation of tensile/shear forces in properly prepared wet pack and tissue overall"?
Anyone can claim anything here.
Without any tangible proof, your claim of "better correlation of tensile/shear forces in properly prepared wet pack and tissue overall" is wild speculation and should be regarded as nothing more than that until you can sustain it with peer-reviewed research.
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Let's make this very simple to illustrate my point why overall disruption characteristic of a given bullet in gel matters -- and not just "permanent cavity" in gel. One fires two different bullets into same gel; bullet A and bullet B. Both bullets penetrate the same distance, say 12", in gel and both expand to same recovered diameter. Bullets A and B, however, have different "temporary cavity" patterns in the gel; gel disruption is greater initially along the bullet path of bullet A but the disruption outside of "permanent cavity" becomes insignificant several inches after impact. Bullet B causes less gel disruption initially, but maintains more disruption along its bullet path for a longer distance. Conclusion: bullet B is likely more effective since it maintains greater velocity toward the end of its path.
Assuming an important body structure or organ is located close to the end of the bullet path, a bullet with greater velocity toward the end of its path might be able to cause disruption of such important structure or organ whereas a bullet with lesser velocity might not. After all, bullet's ability to disrupt is dependent on velocity.
Velocity is zero only when the bullet is at rest, take it as one or two inches from the end of its path instead of "near."
Both bullets, A and B in my example, are decelerating due to non-inertial forces, but bullet B however is maintaining a higher velocity in the last couple of inches or so of its path making it capable of greater disruption to tissue or organ located there.
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So you are apparently unable to substantiate your position on tests that you claim that you've conducted that prove your claim "of better correlation of tensile/shear forces in properly prepared wet pack and tissue overall" so now you offer the sudden diversion of:
There's no need to "make this very simple".
You've made the—as yet unproven—claim that you've conducted testing that supports your prior assertion "of better correlation of tensile/shear forces in properly prepared wet pack and tissue overall" yet refuse to provide the results. Let's see it.
If you wish to elevate the discourse to the level of proving your claims with testing that you offer yet cannot—or will not—provide, no one is required to accept your speculations as being factual. Simply "saying so" does not make it so. If you cannot support your assertion "of better correlation of tensile/shear forces in properly prepared wet pack and tissue overall", your claim remains nothing more than wild speculation until you can prove it with peer-reviewed research.
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RetiredUSNChief
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Lord, I can't believe I'm allowing myself to be sucked into this dumpster fire.
NO.
And that's in response to your posting to which you quoted me as saying:
We're beating a dead horse here.
Ballistics gel is not supposed to "replicate" human tissue...it was never intended to.
KEY WORD in that last: LIKELY.
******
My statement was "Ballistics gel is not supposed to "replicate" human tissue...it was never intended to."
"Replicate" has a different meaning than "simulate". "Replicate" means to reproduce an exact, or nearly exact, copy. The FBI did not intend, nor attempt, to "replicate" soft human tissue at all. They were concerned with the average density of human soft tissue and reduced all other factors out of the equation.
What they did was develop a gel which SIMULATES the average density of human soft tissue. It is homogeneous and other than density has absolutely nothing else in common with soft (or hard) human tissue.
The penetration of a bullet into this medium can therefore said to be COMPARABLE to the penetration into human soft tissue. In a straight forward sense, it's "good enough for government work". So if you "gut shot" a human being with a round which demonstrated a reliable ability to penetrate 12" to 18" in ballistic gel, you SHOULD get a comparable penetration performance in human soft tissue.
BUT...whereas ballistics gel is made by a strict recipe with approved gelatin and maintained at a specific temperature and have their density characteristics checked by a 'calibration' procedure, human beings are NOT so uniformly standardized. Even the procedure by which the test ammunition is shot into the gel is standardized. Shooting into human soft tissue is rarely such a standardized procedure.
There is a far cry between saying something "equates" to something else (meaning "is equal to") and saying something "simulates" something else or "approximates" something else.
At no time does terminal ballistics characteristics measured in ballistics gel EQUATE to terminal ballistics in humans.
Penetration criteria was established not so they could say they can shoot through two people (because 12-18 inches is a bit deeper than most people are thick), but so they can say a particular bullet which demonstrates this capability in ballistics gel is LIKELY to ALSO be able to reliably penetrate a human body deep enough to reach vital organs.
Terminal ballistics is not, never has been, and likely never will be an "exact" science.
I suggest you look at the link posted here months ago in a similar discussion you participated in that presented part of a Ph.D. dissertation that showed results of tensile strength tests of various organs (pigs) showing that muscle tissue is not a good representation of body "soft" tissues. There, like here, you falsely claimed that similarity in bulk modulus and sonic velocity insure that 10% standard gel is a good simulant to body tissues -- without taking into account tensile strength discrepancies in gel vs. tissue.
The issue, as far as my posts are concerned, is validity or lack thereof of simulation of 10% standard ordnance gel to "soft" tissue overall. In order to have validity in such simulation -- relevant FORCES must be closely approximated.
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This—
—is another distraction that has nothing to do with what we are discussing presently.
The matter currently under discussion your ability to provide proof of the claim that you made post #251 that you have conducted testing that supports your speculative position "of better correlation of tensile/shear forces in properly prepared wet pack and tissue overall".
It appears that you have no intention of supporting your speculative musings with the testing and results that you offered above in post #251 of this thread. That you refuse to do so speaks volumes. Carry on.
RetiredUSNChief
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I have a great deal of respect for people on this site. It's not called "The High Road" for nothing.
Keep in mind that my refutation of certain things on this subject are NOT intended to be arguments or stubborn refutation of what I believe or disbelieve on the subject. They are not, in fact, detailed down to precise levels for the simple fact that I have neither read a lot of the references being cited, nor would I believe that level of precision is required.
I am an engineer. Not a doctor, not an attorney, not a ballistics expert, not an employee of an ammunition manufacturing company. I'm soon coming up on 4 decades in the nuclear industry as an operator and engineer and have an education/training background which is, by nature, pretty diverse. Fracture Mechanics? Yep, I can discuss it. Heat Transfer and Fluid Flow? Ditto. Neutron life cycle? Yeppers. Effects of neutron irradiation on structural materials? Uh-huh. Application and extrapolation of various engineering concepts to a wide variety of conditions and circumstances? You betcha.
Human tissue is NOT as "simple" as metallic structures...and metallic structures are actually anything BUT simple themselves, when you're talking about engineering and construction limitations and operating limits.
Add to it the fact that the human being all that tissue is attached to is, itself, an incredibly complex, and tough, critter.
The point of terminal ballistics is to determine the physical effects a particular bullet has on a particular target. With respect to humans, the concern here lies with the physical effect on the human for NON-CNS injuries. In other words, the ability to cause enough tissue damage to incapacitate the human by blood loss and/or drop in blood pressure. Two things directly affect this:
- Penetration (the ability to actually reach deeply enough into the body to reach and damage vital organs which can cause the incapacitation described above).
- Hole size (bigger means more tissue damage due to cutting/tearing and better incapacitation as described above).
The famous (or infamous, if you rather) FBI ballistic gel testing is set up to quantifiably measure the ability of any given bullet to penetrate and (if designed to) expand in soft tissue, as simulated by a homogeneous standardized gelatin medium.
That's it.
And their testing protocol is exacting enough for other people to reliably replicate their efforts in a way which, if performed correctly, will produce comparable results.
Human beings, however, are NOT shot in accordance with FBI ballistics testing protocols. And even if they were, the terminal ballistics derived from such actual shootings WILL vary from their standardized testing protocol results. You cannot, for example, demonstrate an 18" penetration on my body because I'm not 18 inches thick in any direction across my stomach area.
FURTHER: The FBI DOES have statistics on various actual shootings of people and they CAN determine SOME useful information from that. They can say, for example, that victim A was shot with a certain bullet from a certain gun at a certain distance in a certain spot on the body at a certain angle and it did or did not demonstrate certain wound characteristics, such as depth of penetration, torn tissue damage, etc.
From such data, they can draw some conclusions about their own "standard" of penetration and how ammunition which falls within that criteria performs in the real world...in other words, does that famous 12" to 18" minimum penetration characteristic in ballistics gel actually seem to be capable of causing the damage they think it should.
Keep in mind that my refutation of certain things on this subject are NOT intended to be arguments or stubborn refutation of what I believe or disbelieve on the subject. They are not, in fact, detailed down to precise levels for the simple fact that I have neither read a lot of the references being cited, nor would I believe that level of precision is required.
I am an engineer. Not a doctor, not an attorney, not a ballistics expert, not an employee of an ammunition manufacturing company. I'm soon coming up on 4 decades in the nuclear industry as an operator and engineer and have an education/training background which is, by nature, pretty diverse. Fracture Mechanics? Yep, I can discuss it. Heat Transfer and Fluid Flow? Ditto. Neutron life cycle? Yeppers. Effects of neutron irradiation on structural materials? Uh-huh. Application and extrapolation of various engineering concepts to a wide variety of conditions and circumstances? You betcha.
Human tissue is NOT as "simple" as metallic structures...and metallic structures are actually anything BUT simple themselves, when you're talking about engineering and construction limitations and operating limits.
Add to it the fact that the human being all that tissue is attached to is, itself, an incredibly complex, and tough, critter.
The point of terminal ballistics is to determine the physical effects a particular bullet has on a particular target. With respect to humans, the concern here lies with the physical effect on the human for NON-CNS injuries. In other words, the ability to cause enough tissue damage to incapacitate the human by blood loss and/or drop in blood pressure. Two things directly affect this:
- Penetration (the ability to actually reach deeply enough into the body to reach and damage vital organs which can cause the incapacitation described above).
- Hole size (bigger means more tissue damage due to cutting/tearing and better incapacitation as described above).
The famous (or infamous, if you rather) FBI ballistic gel testing is set up to quantifiably measure the ability of any given bullet to penetrate and (if designed to) expand in soft tissue, as simulated by a homogeneous standardized gelatin medium.
That's it.
And their testing protocol is exacting enough for other people to reliably replicate their efforts in a way which, if performed correctly, will produce comparable results.
Human beings, however, are NOT shot in accordance with FBI ballistics testing protocols. And even if they were, the terminal ballistics derived from such actual shootings WILL vary from their standardized testing protocol results. You cannot, for example, demonstrate an 18" penetration on my body because I'm not 18 inches thick in any direction across my stomach area.
FURTHER: The FBI DOES have statistics on various actual shootings of people and they CAN determine SOME useful information from that. They can say, for example, that victim A was shot with a certain bullet from a certain gun at a certain distance in a certain spot on the body at a certain angle and it did or did not demonstrate certain wound characteristics, such as depth of penetration, torn tissue damage, etc.
From such data, they can draw some conclusions about their own "standard" of penetration and how ammunition which falls within that criteria performs in the real world...in other words, does that famous 12" to 18" minimum penetration characteristic in ballistics gel actually seem to be capable of causing the damage they think it should.
Relevant facts are never a distraction to me, but something to be seriously considered.... The comment about wet pack was a response to another poster who assumed that just because I deem gel disruption significant, then so is disruption in wet pack ("magazines"), aside from "permanent" cavity. Since tensile forces in properly prepared wet pack are greater than in 10% standard ordnance gel and more closely approximate tensile forces in tissue (see that Ph.D. dissertation if relevant facts matter to you), I commented that disruption in wet pack outside of "permanent" cavity is not of interest to me.
If nothing else, it seems that the false notion of necessary and sufficient condition of bulk density and sonic velocity equivalency for 10% standard gel to soft tissue bullet penetration/expansion "equivalency" has been debunked; the remaining stumbling block seems to be "equivalency" of viscous forces in gel vs. various forces in tissue. Fortunately, for those who are fact-minded that question has been adequately addressed by the data presented in that Ph.D. dissertation referenced before. Carry on!
The above is precisely why I consistently commented that any "equivalency" between what a bullet does to a body (and no two bodies are really "equivalent" to each other) and any simulant is for bullet penetration and expansion purposes, nothing else really. This position differs, of course, from Fackler, Roberts, and whoever else is like-minded.
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Try as you may to change the present subject (which is your claimed ability to support the speculative position "of better correlation of tensile/shear forces in properly prepared wet pack and tissue overall"); for those who are actually ''fact-minded'' it remains clearly evident that you've yet to provide any actual proof that your speculative musings are valid. So you've conducted testing which have produced findings that demonstrate the "better correlation of tensile/shear forces in properly prepared wet pack and tissue overall"? Where might your test findings be reviewed for those who are indeed "fact-minded"?
Try as you may to change the present subject (which is your claimed ability to support the speculative position "of better correlation of tensile/shear forces in properly prepared wet pack and tissue overall"); for those who are actually ''fact-minded'' it remains clearly evident that you've yet to provide any actual proof that your speculative musings are valid. So you've conducted testing which have produced findings that demonstrate the "better correlation of tensile/shear forces in properly prepared wet pack and tissue overall"? Where might your test findings be reviewed for those who are indeed "fact-minded"?
If you become fact-minded first try to learn something from the tensile strength tests of various tissues presented in research that I previously mentioned; however, if you still adhere to the false notion that you repeatedly expressed over time about necessity and sufficiency of bulk modulus and sonic velocity equivalency to insure simulant "equivalency" to soft-tissue, then no findings will be relevant.
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Gee, what would you guys do if a bullet actually hit a bone?
That depends on which bullet, which bone, and what part of bone is impacted. Things are generally not simple...
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