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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.
Advanced techniques are the basics mastered.
Excellence is an art won by training and habit. We are what we repeatedly do. -- Aristotle
Pistol/Shotgun/Rifle Instructor
Sig/Remington/RRA/Sabre Armorer
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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.
My capacity for self deception is exceeded only by yours.
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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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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.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 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)
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.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.
Last edited by Shawn Dodson; 12-04-12 at 16:28.
Shawn Dodson
Member
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.
Member
Wrong. Doctor Roberts has directly stated that Perma Gel doesn't work, and there are no other tissue simulants currently in use that compare to 10% ordnance gelatin. In the case of Perma-Gel - it was tested by Doctor Roberts and found to be unsuitable as a tissue simulant, although it was useful as a backer material when testing ballistic vests.Originally Posted by AndrewWiggin
The best suggestion I have for you is to read Duncan McPherson's book on the subject that explains what is required of a good tissue simulant. It takes longer than I care to type out. Suffice it to say: There is certainly a desire to use tissue simulants other than ballistic gel due to gel's sensitivity in how it's prepared and the fact that you can only store blocks for two days. The Army is currently conducting research into physically associative gels (PAGs). I don't yet know how likely they are to replace properly calibrated BG.
Member
Wrong? What is wrong? That private citizens may or may not demand the same level of accuracy? That's an expression of an opinion and simply can't be right or wrong.
I think what you're getting at is that the gelatin substitutes aren't suitable for lab use. I'm sure you are correct. You know a whole hell of a lot more on this subject than I do but you can't possibly be trying to say that they aren't useful at all, to anyone, because multiple tests performed by independent people have shown reasonably accurate results, compared to published data on well known cartridges. If a wide range of pistol, shotgun, and rifle tests show penetration and projectile upset results roughly consistent with published results from ordnance gelatin, that is sufficient for me. Am I going to base my decision on carry ammo on it? Not likely, but it is interesting.
It is interesting to see data on cartridges and loads that haven't seen a lot of testing. I respect you but until someone can give me a quantitative reason that I should ignore the similarity between these mediums and calibrated 10% ordnance gelatin, I am going to maintain the position that they are reasonably analogous. Not precisely the same but close enough that I can say "Wow, nice expansion and adequate penetration," or "Holy fragmenting piece of crap, Batman, that thing didn't even make six inches!"
I'll still keep 180 gr Gold Dots in my G23 and I'll still keep 75 gr Prvi Partisan in my home defense rifle.
Senior Member
Many of the polymer gel simulants we have seen are OK for rough handgun penetration data, but generally fail to adequately capture and represent the TSC associated with rifle caliber projectiles. As a result, at this time they are not the best choice for a tissue simulant.
Water is a less than ideal media, but is simple and cheap--giving a rough assessment of maximum expansion characteristics of JHP handgun projectiles.
To date, adequately prepared, correctly stored, and properly calibrated ordnance gel remains the best simulant for assessing penetrating projectile characteristics. When interpreted correctly, it does have a very good track record at accurately reflecting results of actual shooting incidents involving human tissue--it is not just useful for comparing projectiles to one another.
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Doc, could you give us some rough numbers on gel simulants for handgun calibers? What are typical discrepancies compared to ballistic gelatin (in %) when you measure expansion and penetration?
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