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Thread: Predictive tests in water

  1. #21
    Site Supporter DocGKR's Avatar
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    "Are commercial ammo producers using these models?"
    Let's hope they are not relying on the ARL type models, as these have some serious issues.

    High speed video has a place, especially with some close range rifle testing, but it is generally NOT needed for most routine handgun, shotgun, and long range rifle testing, as proven by the LAIR, FBI BRF, JSWB-IPT, etc... testing.
    Facts matter...Feelings Can Lie

  2. #22
    Site Supporter PNWTO's Avatar
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    Is there any data you are using that is GWTO-era?
    Last edited by PNWTO; 08-16-2018 at 03:11 PM.
    "Do nothing which is of no use." -Musashi

    What would TR do? TRCP BHA

  3. #23
    Quote Originally Posted by DocGKR View Post
    Let's hope they are not relying on the ARL type models, as these have some serious issues.

    Would you be willing to provide a more detailed explanation regarding the issues that the ARL models suffer from?

    I would really appreciate your insight on the topic and I am sure that others here would, too.
    Last edited by the Schwartz; 08-16-2018 at 04:00 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.

  4. #24
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    *popcorn*
    This is like Dr. Courtney all over again, but with an open mind, real data, and desire for dialogue. I hope to learn things.

  5. #25
    Quote Originally Posted by Unobtanium View Post
    *popcorn*
    This is like Dr. Courtney all over again, but with an open mind, real data, and desire for dialogue. I hope to learn things.

    So do I.

    If Doc can enlighten me (and everyone else here) as to the 'how' and the 'why' the BRL P[I/H] models are flawed, I will consider myself that much better off; although being a 'nerd' in the classic sense, all mathematical models, even flawed ones relating to P[I/H], will always fascinate me. I look forward to, and stand ready to, absorb his input.

    Just the same, the two bullet penetration models (one based on the Poncelet form and the other upon the modified THOR power law) stand on solid ground (with superior ANOVAs) as they are correlated against nearly 900 data from 14 independent sources.
    Last edited by the Schwartz; 08-16-2018 at 09:09 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.

  6. #26
    Duncan MacPerson once observed, "Bullshit + mathematics = bullshit."

    BRL formulae are overly-complicated bullshit applied to a simple problem.

    Soft barrier materials, i.e., fabric, needs to be shored (placed) against the test medium to duplicate the conditions encountered by a penetrating handgun bullet that will produce the cookie-cutter effect to clog the hollowpoint cavity with a fabric plug.

  7. #27
    Quote Originally Posted by Shawn Dodson View Post
    Duncan MacPerson once observed, "Bullshit + mathematics = bullshit."

    BRL formulae are overly-complicated bullshit applied to a simple problem.

    Soft barrier materials, i.e., fabric, needs to be shored (placed) against the test medium to duplicate the conditions encountered by a penetrating handgun bullet that will produce the cookie-cutter effect to clog the hollowpoint cavity with a fabric plug.
    First, in reverse order, re: barrier materials; Yes, that is how I've always done it, materials are shored firmly against the test medium. That's easy enough to do with water cartons and the alternate method of testing with water-filled 1-gallon storage bags lined up in a PVC trough.

    Quote Originally Posted by Shawn Dodson View Post
    BRL formulae are overly-complicated bullshit applied to a simple problem.
    And second: OK. How so? I am all ears. Well, I s'pose that it is more like ''I am all eyes'' what with having to read the typed words on my 'puter.

    Specifics please.
    Last edited by the Schwartz; 08-16-2018 at 11:56 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.

  8. #28
    Another example of some of the independent data used to correlate the ever-so-slightly modified Poncelet form and the mTHOR model:

    A one-ounce Brenneke USA Tactical Home DefenseŽ (THD) 12-gauge slug was fired from a Remington 870 12-gauge shotgun into bare calibrated 10% ordnance gelatin which was validated by a .177-caliber BB at a depth of 8.89 centimeters.

    The 430.8 gr. Brenneke Tactical Home DefenseŽ (THD) slug (pictured below) struck the gelatin test block at a velocity of 1,256.6 feet per second, expanded to an average diameter of 0.888 inch and penetrated to a maximum depth of 17.75 inches.
    The recovered weight of the 12-gauge Brenneke Tactical Home DefenseŽ (THD) slug was 419.8 gr.
    No significant fragmentation or loss of mass (a loss of 11 grains or 2.55% is noted) occurred.

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    Comparing the gelatin-derived test data-

    Average Expansion: 0.888 inch
    Recovered Slug Weight: 419.8 grains (97.45% retained weight)
    Impact Velocity: 1,256.6 fps
    Maximum Penetration Depth: 17.75 inches

    -to the predictive yields of the Q-model and mTHOR model, it is easy to see that both models correlate well to the gelatin-derived test data.

    Q-model
    DoP: 17.520 inches
    Wound Mass: 5.343 ounces
    Wound Volume: 8.888 cubic inches

    mTHOR
    DoP: 19.029 inches
    Wound Mass: 5.804 ounces
    Wound Volume: 9.654 cubic inches

    Probability of Incapacitation, 1st-shot and cumulative binomial P[I/H] values
    1st-shot P[I/H]: 86.32%
    2nd-shot P[I/H]: 98.13%
    3rd-shot P[I/H]: 99.74%
    ΔE15: -884.539 fpe

    DoP = maximum equivalent depth of penetration in calibrated 10% ordnance gelatin
    Wound Mass = total weight of tissue damaged/destroyed within the entire wound channel
    Wound Volume = volume of the entire wound channel
    P[I/H] = probability of incapacitation per random munition strike to combatant's torso/abdomen: Assault, 30-second time-frame (US Army BRL P[I/H] model, Dziemian, 1960)
    ΔE15 = Amount of kinetic energy (in fpe) expended by the bullet from a penetration depth of 1 through 15 centimeters
    Last edited by the Schwartz; 08-17-2018 at 12:36 AM.
    ''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.

  9. #29
    Since so-called 'economy' ammunition appeals to my 'financially responsible' side (and yes, I have often been referred to as being a ''cheap-ass''), occasionally I get the desire to test such inexpensive fodder. Typically, I fire two or three test rounds without a barrier and against various types and weights of clothing so that my test sample is greater than '1'. The test of this ammunition through 'light clothing' will follow this one.

    Test #1: Federal .45ACP 230-grain Hi-Shok JHP, standard pressure (C45D)

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    Diameter: 0.7749 inch
    Weight: 216.4 gr. (94.09% retained weight)
    Velocity: 877 fps

    Test Firearm: unmodified HK USP45 with a 4.41-inch barrel
    Test Range: 3 meters (~10 feet)
    Test Medium: H2O @ ~78° Fahrenheit
    Barrier: none

    Frontal Expansion Face #1:

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    Rear, test #1:

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    The average expanded diameter of the Federal .45ACP 230-grain Hi-Shok JHP (C45D) test projectile was obtained by measuring the two maximum and minimum expansion face dimensions across the leading edge of the projectile's expansion face where the flow field separates from the edge of the test projectile. In this first of two tests of the Federal .45ACP 230-grain Hi-Shok JHP (C45D), the two minimum expansion dimensions of the test Federal .45ACP 230-grain Hi-Shok JHP were 0.763'' and 0.7605'' and the two maximum expansion dimensions were 0.790'' and 0.786''. The average expanded diameter was calculated at 0.774875''. Recovered length of this test round was measured as 0.441''. Weight measurements of the recovered test projectile (and its jacket) were obtained using an RCBS Model 505 magnetically-dampened reloading scale.

    Predictive Analysis:

    Q-model
    DoP: 9.545 inches
    Wound Mass: 2.217 ounces
    Wound Volume: 3.687 cubic inches

    mTHOR
    DoP: 9.872 inches
    Wound Mass: 2.293 ounces
    Wound Volume: 3.814 cubic inches

    Probability of Incapacitation:
    1st-shot P[I/H]: 73.25%
    2nd-shot P[I/H]: 92.85%
    3rd-shot P[I/H]: 98.09%
    ΔE15 : -276.233 fpe

    DoP = maximum equivalent depth of penetration in calibrated ordnance gelatin (or soft tissue)
    Wound Mass = total weight of tissue damaged/destroyed within the entire wound channel
    P[I/H] = probability of incapacitation per random projectile strike to assailant's torso/abdomen: 30-second Assault modality, (Dziemian US Army BRL P[I/H] model)
    ΔE15 = amount of kinetic energy, in fpe, expended by the bullet from a penetration depth of 1 through 15 centimeters

    With an average predicted maximum penetration depth of 9.709 inches (the average of the Q-model and mTHOR model penetration depth predictions) and a 1st-shot P[I/H] of 73.25%, the Federal .45ACP 230-grain Hi-Shok JHP (C45D) demonstrates relatively shallow predicted penetration. In spite of this deficiency, the Federal .45ACP 230-grain Hi-Shok JHP (C45D) should be relatively effective given its predicted 1st-shot P[I/H] of 73.25%. A "double-tap' with ammunition, which comes as a highly recommended and technically-sound self-defense tactic gives this particular Federal .45ACP 230-grain Hi-Shok JHP (C45D) a 2nd-shot P[I/H] of 92.85%.

    ***It should also be noted that while the gilding metal jacket did separate from the fully expanded lead core, it was found lying right next to the expanded lead core (about ˝ of an inch away) in the test water column meaning that the jacket remained with the lead core throughout the entirety of the penetration event. For that reason, the gilding metal jacket's remaining mass (~22.6 grains) was included in the recovered weight of the Federal .45ACP 230-grain Hi-Shok JHP for the purpose of computing the predictive analysis of this water test.


    While I am thinking of the BRL P[I/H] model (e.g.: Dziemian, 1960) and the yields that I have used in prior posts in this thread, I'd also like to take the time to clarify the position that I hold regarding the use and implications of the P[I/H] metric and all of the equations associated with that metric. I am very thick-skinned and I simply do not take myself, or any version of these P[I/H] models, so seriously that I would ever take offense towards anyone expressing their opinion, opposing or in favor of, the use and yields of these P[I/H] models. The P[I/H] models, produced by Sturdivan and Bruchey, Dziemian et. al., and Kokinakis and Sperrazza, are not of my creation and, as a result, I an unable to take offense from view points that find fault or disagree with the implications of these types of P[I/H] models. I include the yields of these P[I/H] models simply because I enjoy such algorithms for what they are in my own very 'nerdy' perspective....a lot of fun: statistical experimental design, analytical mathematics. With this thought, I welcome any well-reasoned opinion on this matter and any other topic.

    On the other hand, if anyone questions the bullet penetration models of my own creation, I reserve the right to run around my office, knocking my desk and chair over, pulling out what little hair I have left all while yelling, "No, no, no, no, no!....I am not listening!....no, no, no, no, no!''
    Last edited by the Schwartz; 08-17-2018 at 12:20 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.

  10. #30
    OK, as promised, here is the second test of the Federal .45ACP 230-grain Hi-Shok JHP against 'light clothing'...

    Test #2: Federal .45ACP 230-grain Hi-Shok JHP, standard pressure (C45D)

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    Diameter: 0.7889 inch
    Weight: 221.8 gr. (96.43% retained weight)
    Velocity: 891 fps

    Test Firearm: unmodified HK USP45 with a 4.41-inch barrel
    Test Range: 3 meters (~10 feet)
    Test Medium: H2O @ ~78° Fahrenheit
    Barrier: 4 layers of 1-ounce cotton T-shirt fabric

    Frontal Expansion Face #2:

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    Rear, test #2:

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    The average expanded diameter of the Federal .45ACP 230-grain Hi-Shok JHP (C45D) the test projectile, which was fired through light clothing in this test, was obtained by measuring the two maximum and two minimum expansion face dimensions across the leading edge of the expansion face where the flow field separates from the edge of the test projectile. In this second of two tests of the Federal .45ACP 230-grain Hi-Shok JHP (C45D), the two minimum expansion dimensions of the second test Federal .45ACP 230-grain Hi-Shok JHP were measured at 0.784'' and 0.786'' and the two maximum expansion dimensions were measured at 0.7875'' and 0.798''. The average expanded diameter was computed at 0.788875''. Recovered length of this test round was measured as 0.404''. Weight measurements of the recovered test projectile were obtained using an RCBS Model 505 magnetically-dampened reloading scale. No evidence of jacket/core separation was observed.

    Analysis:

    Q-model
    DoP: 9.509 inches
    Wound Mass: 2.289 ounces
    Wound Volume: 3.807 cubic inches

    mTHOR
    DoP: 9.878 inches
    Wound Mass: 2.378 ounces
    Wound Volume: 3.955 cubic inches

    Probability of Incapacitation:
    1st-shot P[I/H]: 74.07%
    2nd-shot P[I/H]: 93.28%
    3rd-shot P[I/H]: 98.26%
    ΔE15 : -292.893 fpe

    DoP = maximum equivalent depth of penetration in calibrated ordnance gelatin (or soft tissue)
    Wound Mass = total weight of tissue damaged/destroyed within the entire wound channel
    P[I/H] = probability of incapacitation per random projectile strike to assailant's torso/abdomen: 30-second Assault modality, (Dziemian US Army BRL P[I/H] model)
    ΔE15 = amount of kinetic energy, in fpe, expended by the bullet from a penetration depth of 1 through 15 centimeters

    With an average predicted maximum penetration depth of 9.694 inches (the average of the Q-model and mTHOR model penetration depth predictions) and a 1st-shot P[I/H] of 74.07%, the Federal .45ACP 230-grain Hi-Shok JHP (C45D) demonstrates relatively shallow predicted penetration. Even though both test shots suggest the tendency of this JHP design towards shallow penetration depth for this ammunition, I suggest that it should still serve reasonably well in the role of a self-defense round in typically encountered environs.
    Last edited by the Schwartz; 08-17-2018 at 03:03 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.

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