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Thread: Ballistic gelatin comparisons: Part I

  1. #71
    Site Supporter the Schwartz's Avatar
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    Quote Originally Posted by DocGKR View Post
    I am on 24 hour call today and don't know where that data is at the moment--it is not on my current computer. We just finished a kid with a maxillary fracture from a bike accident, are working up an older adult who will need surgery for their bicycle induced orofacial injures, as well as trying to get OR time for a person with a jaw tumor, so I am unsure when I will be able to look for that information.

    Our service has never been busier and I have not had less than a 12 hour day in months--with many extending to 18 hours.

    No problem, Doc. I am digging around here and will locate it. Take care of yourself and get some rest.


    ETA: OK, think that I located the associated data:

    9 mm Speer 147 gr G2 at 955 fps (accuracy 95-0x):
    BG: Pen = 13.8”, RD = 0.53”, RL = 0.45”, RW = 147.5 gr
    4LD: Pen = 20+”, RD = 0.35”, RL = 0.65”, RW = 147.0 gr (all rounds failed to expand)
    AG: Pen = 10.5”, RD = 0.65”, RL = 0.54”, RW = 147.5 gr
    Last edited by the Schwartz; 11-16-2019 at 09:44 PM.
    ''Politics is for the present, but an equation is for eternity.'' ―Albert Einstein

    Full disclosure per the Pistol-Forum CoC: I am the author of Quantitative Ammunition Selection. www.quantitativeammunitionselection.com

  2. #72
    Quote Originally Posted by DocGKR View Post
    I am on 24 hour call today and don't know where that data is at the moment--it is not on my current computer. We just finished a kid with a maxillary fracture from a bike accident, are working up an older adult who will need surgery for their bicycle induced orofacial injures, as well as trying to get OR time for a person with a jaw tumor, so I am unsure when I will be able to look for that information

    Our service has never been busier and I have not had less than a 12 hour day in months, with many extending to 18 hours--have very little time for other endeavors at the moment.
    Lots of folks need you more than us. Thanks for all the work you do.


    Sent from my iPhone using Tapatalk

  3. #73
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    Part 2 of the article is posted. But don't expect to see any results. This author is saving the results for a 3rd article.

    https://www.policeone.com/police-pro...pfONSxRFxBwTL/

  4. #74
    I am curious if part of the penetration discrepancy between Clear Gel and ballistic gelatin is related to the temperature of the medium. Ballistic gelatin is chilled to 39F while Clear Gel is used at whatever the ambient air temperature is at it's storage and testing location. Could temperature differences in Clear Gel also explain variations in different Clear Gel tests I have seen? One specific test that comes to mind is MrGunsnGear test of Federal 130 HST +P 38 Special in Clear Gel exhibited 16 inches of penetration with a J frame while my own Clear Gel test with a Ruger LCR gave 11.75 inches of penetration (Which is identical to the only calibrated Vyse 10% ballistic gelatin test I have found for this round, posted on M4C). I have two 16 inch Clear Gel blocks so I will refrigerate one and see if there is a difference in penetration.

  5. #75
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    Wow. Just saw this thread and read the two articles. I need to start writing, just to balance out the wackadoo factor.

  6. #76
    Site Supporter DocGKR's Avatar
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    Could temperature differences in Clear Gel also explain variations in different Clear Gel tests I have seen?
    Unlikely, as they are entirely different materials with different chemical and physical properties compared to organically derived ordnance gelatin.
    Facts matter...Feelings Can Lie

  7. #77
    Site Supporter the Schwartz's Avatar
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    Quote Originally Posted by CZ Man View Post
    Part 2 of the article is posted. But don't expect to see any results. This author is saving the results for a 3rd article.

    https://www.policeone.com/police-pro...pfONSxRFxBwTL/
    Thanks for the link, CZ Man.

    Of the information presented in that linked article, the part that I find most "telling" is the following paragraph in which the author describes the glaring difference in terminal behavior of the exact same round, fired under the exact same conditions:

    In Hornady’s tests of its 9mm +P, 135 grain, Critical Duty Flexlock bullet, the projectile normally penetrated around 14.5 inches in bare, calibrated gelatin. Independent testing of this projectile by the US Department of Homeland Security (14 inches) and the FBI (14 inches), as well as joint Hornady/agency testing with the Mesa (Arizona) Police Department (14 inches), Nebraska State Patrol (14.75 inches) and the Texas Department of Public Safety (14.25 inches), validated this performance (using a variety of pistol makes and barrel lengths) and confirmed Hornady’s expectation for this projectile. However, when Hornady tested the same ammunition in the clear, synthetic gelatin substitute (same test protocol and conditions, including barrel length and lack of an intermediate barrier) the 9mm FlexLock bullet penetrated around 19 inches. This represented a 31% increase in penetration in the clear synthetic product compared to FBI-calibrated gelatin.
    To put a finer point on this issue, I quote a particularly relevant portion of a post made earlier in this thread by Dr. Roberts:

    Quote Originally Posted by DocGKR View Post
    Second--every institution I am aware of that conducts valid terminal ballistic testing for LE and mil purposes regularly tests alternative tissue simulants, including clear synthetic test media, to see if new advances offer a more effective option than 10% ordnance gel. So far I am unaware of any simulant which has proven to offer superior terminal performance results in the lab than properly fabricated and validated 10% ordnance gelatin.
    Concisely put, based upon Dr. Roberts' comprehensive experience and input, I doubt that anything ground-breaking is going to emerge from the third part of the article that has not already been demonstrated by at least three other independent sources who have also evaluated Clear Ballistics Gel against validated 10% ordnance gelatin: the Clear Ballistics Gel product is simply not suitable for use as a valid tissue simulant.
    Last edited by the Schwartz; 12-29-2019 at 06:37 PM.
    ''Politics is for the present, but an equation is for eternity.'' ―Albert Einstein

    Full disclosure per the Pistol-Forum CoC: I am the author of Quantitative Ammunition Selection. www.quantitativeammunitionselection.com

  8. #78
    Site Supporter DocGKR's Avatar
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    Correct.

    Also, keep in mind that ordnance gel blocks are "validated", not "calibrated".....
    Facts matter...Feelings Can Lie

  9. #79
    I don't know if anyone still cares, and I just flipped through the thread and didn't see it posted. Here's part 2. Hint: for results, wait for part 3

    https://www.policeone.com/police-pro...pfONSxRFxBwTL/

  10. #80
    Part 3

    IMPLICATIONS

    With respect to the tested product, our results suggest the following implications:

    • The clear synthetic gelatin must be calibrated by the user before use.

    The factory warranty cards cannot be relied upon to give an accurate measure of the product’s calibration.

    • The clear synthetic gelatin currently demonstrates a tendency to limit bullet expansion and increase bullet penetration, compared to FBI-standard, 10% calibrated organic gelatin.

    Based on our limited sample, this tendency seems to apply irrespective of bullet manufacturer, materials, design, construction, weight, pressure, or velocity. It seems that bullets penetrate significantly more in the clear synthetic, even when acceptable variations in organic gelatin penetration depth are accounted for.

    • The clear synthetic gelatin currently does not appear to be a suitable substitute for FBI-standard, 10% calibrated organic gelatin if the bullets will be measured and evaluated according to FBI performance standards.

    Because the bullets we tested behaved so differently in the clear synthetic gelatin versus the 10% calibrated organic gelatin, it’s not appropriate to use the FBI standards ‒ which were designed to be applied to 10% calibrated organic gelatin – to measure bullet performance in the clear synthetic product.

    In example, it’s inappropriate to measure and evaluate bullet penetration according to the FBI protocol (which rewards bullets that penetrate between 12” and 18” in 10% calibrated gelatin and penalizes those that fall outside this window) when bullets may routinely penetrate an extra 6” in the clear synthetic. If we did apply FBI standards to the clear synthetic, we might “pass” a bullet that normally fails the FBI protocol because it doesn’t penetrate deeply enough. Conversely, we might “fail” a bullet because it over penetrates in the clear synthetic, even when it normally passes the FBI protocol because by remaining within FBI penetration limits.

    • There is no apparent “conversion” between data derived from 10% organic gelatin and the current version of the clear synthetic.

    Unfortunately, our limited test doesn’t indicate a conversion “shortcut” is likely. It would be convenient if we could develop a conversion factor that would equate the organic gelatin and clear synthetic gelatin, but our data indicate that bullet performance is too variable in these mediums to develop a universal “rule of thumb.” Perhaps a skilled mathematician could derive a constant from a more complete sample, but we’re not seeing one lurking in the data.

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