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Thread: Clear Ballistics Gel and Perma-Gel

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    Clear Ballistics Gel and Perma-Gel

    I know Dr Roberts has said Perma-Gel is not a good tissue simulant for testing. Is the same true of the Clear Ballistics gel?

    What makes Perma-Gel (and possibly Clear Ballistics Gel) poorly suited for testing? They seem to offer some advantages (temperature stable, clear, and they won't mold/rot) but I don't want to waste my time if any results with them are useless.
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    I'm not sure. I've heard the same thing but no one has offered an objective, empirical reason. I'd like to see a series of tests with well documented rifle, pistol, and shotgun rounds to determine whether it produces results consistent with calibrated 250A bloom gelatin or not. If it doesn't, well, there's your answer. If it does, then it may simply be some institutional inertia at work.

    I think there's a big disconnect between what is suitable for a lab doing government contract work and what is suitable for the private citizen looking to determine in a very general way what the performance capabilities of a particular cartridge are.

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    Man, I might be way off base with this comment, but here goes...

    10% gel is not any better at being a tissue simulant than perma gel, but it is the industry standard and thus used to compare load to load.

    Where this gets sticky in my mind is that the permagel results may be close to 10% but they are not identical and thus the temptation is to compare permagel results to 10% results and that would not be an accurate comparison.

    on the flipside, some guys are doing a BB calibration before they shoot (and getting correct pentrations)... could that be used to compare to 10%?

    So, heres the cool part. There is a guy on youtube (tnoutdoors9) who does a ton of permagel tests and actually does a half decent job at measuring and comparing the results. he's got a large enough body of comparative testing at this point that one could begin using those results constructively.

    To be honest, I compared a bunch of tnoutdoors9 shot results to Doc and others 10% results and they are very very close. close enough that for my purposes a well done permagel shot is good enough for me to begin my own experiments and testing.

    as a cool aside, this is the ONLY area that anything new is being done for the 10mm, and it's yielding some good and (mostly) predictable results, further validating it in my mind.

    I still focus on shot placement and frequency as my primary means of wounding tho
    Last edited by Jack-O; 12-04-12 at 10:43.
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    That's a good point. Clear Gel, Permagel, Simtest, and even calibrated 10% ordnance gelatin, for that matter, are not very good at predicting what bullets will do in tissue. For that matter, what bullets *did* in tissue is not very good at predicting what bullets *will* do in tissue. What 10% ordnance gelatin is good at is being a consistently repeatable medium that allows different people to compare bullets in a meaningful way.

    Tnoutdoors9's tests are generally consistent with well published loads, in the areas that he has tested something that was also tested by a "real" lab. It bothers me that he only posts his BB calibration depth and not the velocity, though. Most of his 10mm tests have been consistent with mine, though one test was dramatically different. He got way different results from Underwood's 180gr Gold Dot than I got from a hand load of the same bullet at the same velocity range.

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    That's a good point. Clear Gel, Permagel, Simtest, and even calibrated 10% ordnance gelatin, for that matter, are not very good at predicting what bullets will do in tissue.
    The test of the wound profiles’ validity is how accurately they portray the projectile-tissue interaction observed in shots that penetrate the human body. Since most shots in the human body traverse various tissues, we would expect the wound profiles to vary somewhat, depending on the tissues traversed. However, the only radical departure has been found to occur when the projectile strikes bone: this predictably deforms the bullet more than soft tissue, reducing its overall penetration depth, and sometimes altering the angle of the projectile’s course. Shots traversing only soft tissues in humans have shown damage patterns of remarkably close approximation to the wound profiles.

    The bullet penetration depth comparison, as well as the similarity in bullet deformation and yaw patterns, between human soft tissue and 10% ordnance gelatin have proven to be consistent and reliable. Every time there appeared to be an inconsistency…a good reason was found and when the exact circumstances were matched, the results matched. The cases reported here comprise but a small fraction of the documented comparisons which have established 10% ordnance gelatin as a valid tissue simulant.


    --“The Wound Profile & The Human Body: Damage Pattern Correlation.” (Martin L Fackler, MD, Wound Ballistics Review, 1(4): 1994; 12-19)

    Tnoutdoors9's tests are generally consistent with well published loads, in the areas that he has tested something that was also tested by a "real" lab. It bothers me that he only posts his BB calibration depth and not the velocity, though.
    It's unfortunate that Tnoutdoors9 misinterprets disruption produced by temporary cavitation and describes it to his viewers as permanent disruption. The "damage" produced in his test simulant does not correlate to damage produced in soft tissues.
    Last edited by Shawn Dodson; 12-04-12 at 16:28.
    Shawn Dodson

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    Let me clarify: I'm not saying that ballistic gelatin results are without merit. I'm just saying that the interaction of a projectile and tissues often involve many variables that are difficult to reproduce or control for. Ballistic gelatin is the industry standard tissue simulant and it is perfectly adequate for the intended task. Other mediums may perform well but I am unaware of any testing that indicates whether the results from the other mediums are analogous to 10% ordnance gelatin.

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    I agree. The first few times I heard it I thought he had misspoken but it seems he is unaware of what TSC and crush cavity actually are. Nevertheless, his measurements are thorough enough that you can draw your own conclusions, if you believe his medium to be reasonably similar to 10% ordnance gelatin.

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    I'm just saying that the interaction of a projectile and tissues often involve many variables that are difficult to reproduce or control for.
    I understand what you're saying but these "many variables" really don't matter.
    Shawn Dodson

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    I think we're quibbling over a matter of scale.

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    Quote Originally Posted by Altair View Post
    I know Dr Roberts has said Perma-Gel is not a good tissue simulant for testing. Is the same true of the Clear Ballistics gel?

    What makes Perma-Gel (and possibly Clear Ballistics Gel) poorly suited for testing? They seem to offer some advantages (temperature stable, clear, and they won't mold/rot) but I don't want to waste my time if any results with them are useless.
    This PDF has information on the recent development of physically associating (copolymer) biomimetic gels

    http://www.dtic.mil/dtic/tr/fulltext/u2/a481959.pdf

    and offers favorable comparison of these newer tissue surrogates to calibrated ordnance gelatin in terms of their mechanical response to the passage of projectiles- namely density, bulk modulus, short-time and long-time strain rates, and radial inertial properties- the chief advantage being that the copolymer gels offer greater thermal stability than ordnance gelatin.

    The clear gels being used most recently seem to be of this class of material, but there doesn't seem to be a lot of correlative research that would serve to establish their dynamic equivalence with calibrated ordnance gelatin. It would be nice to see more.
    Last edited by 481; 12-05-12 at 23:11.

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