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Thread: 9 mm 147 gr duty load testing

  1. #221
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    Quote Originally Posted by Rich_Jenkins View Post
    @DocGKR

    Thanks as always for your expertise and advice.

    I am a low volume armed civilian, and it is time to order some more defensive ammo.

    Since this thread was started, has Federal HST 147 continued to perform as expected in "real world" situations?

    Thank you again.

    Rich
    Yes.

    Provided you utilize good shot placement and the appropriate tactics, before your adversary can do the same to you.

  2. #222
    Site Supporter DocGKR's Avatar
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    Beat-Trash hits it out of the park!
    Facts matter...Feelings Can Lie

  3. #223
    Site Supporter 0ddl0t's Avatar
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    (I'm not randomly necroposting, the glock 43 thread referenced here...)

    Quote Originally Posted by BehindBlueI's View Post
    What about the 3.1"-ish barrels like Glock 43 or Shield?
    Quote Originally Posted by michael1778 View Post
    In situations like that, consider the heavier loadings (like 147 grain) so the muzzle velocity is very close to the fraction of an inch longer versions. 147 grain loads from the recommended list with ~3 inch barrels should be good performers. In a similar fashion, I use 180 grain loads from the recommended list in my .40S&W M&P Shield and M&P 40 compact.
    Quote Originally Posted by DocGKR View Post
    Correct.
    DocGKR: Have you tested 147 gold dots from a 3 or 3.1" barrel? 2 of 5 failed to expand and overpenetrated in Shootingthebull's denim test, but he was using clear gel at that time. But if there is going to be any difference, I'd expect bullets to expand more in clear gel than organic...

    147 HST's performed fine in organic gel but was on the short end of penetration (with larger expansion)

    4 out of 5 147 Ranger T's performed fine in organic gel, penetrating deeper but expanded less (1 of the 5 bullets chrono'd slower and only partially expanded)

    Quote Originally Posted by QED View Post
    From MacPherson (IWBA 1998):" The standard deviation of the penetration depths is the best measure of consistency of bullet expansion and is small in bare gelatin for well designed bullets. The recommended value of this parameter is 0.6" which is easily met by well designed JHP bullets."
    Just a quick statistics refresher: 99.7% of data is expected to fall within + or - 3 SD. That would be a spread of 3.8" penetration.

    95% of data is expected to fall within + or - 2 SD. That would be a spread of 2.4" of penetration.




    And that is assuming the distribution is random. So there is not much sense quibbling over a 2" discrepancy between 2 people on 2 different days with 2 different gel blocks (with unpublished bb calibrations). As Carveth Read noted, "It is better to be vaguely right than exactly wrong."

  4. #224
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    Quote Originally Posted by 0ddl0t View Post

    <snip>


    And that is assuming the distribution is random. So there is not much sense quibbling over a 2" discrepancy between 2 people on 2 different days with 2 different gel blocks (with unpublished bb calibrations). As Carveth Read noted, "It is better to be vaguely right than exactly wrong."
    In the context of your statistics refresher, referring to a normal distribution, which is the only distribution you discussed, as "a random distribution" is imprecise, to use a charitable adjective...

    Why do you assume a normal distribution applies here?

  5. #225
    Site Supporter 0ddl0t's Avatar
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    Quote Originally Posted by DMWINCLE View Post
    In the context of your statistics refresher, referring to a normal distribution, which is the only distribution you discussed, as "a random distribution" is imprecise, to use a charitable adjective...

    Why do you assume a normal distribution applies here?
    The 68, 95, 99.7 rule applies only to normal distributions where X is distributed randomly. If the distribution is not normal, you have to fall back on theorems like Chebyshev's which broaden the probability of data falling within 2 SD of the mean from 95% to 75% and from 99.7% to 89% for 3 SD.

    That would make quibbling over a ~ +/- 2 SD discrepancy between 2 testers on 2 different days even more asinine...
    Last edited by 0ddl0t; 03-08-2019 at 11:36 AM.

  6. #226
    You've got this backwards;

    Quote Originally Posted by 0ddl0t View Post
    But if there is going to be any difference, I'd expect bullets to expand more in clear gel than organic...
    As stated elsewhere in this forum in another thread:

    Quote Originally Posted by the Schwartz View Post
    Dr. Roberts has accurately defined the issues involving the use of Clear Ballistics Gelatin and all similar bio-mimetic co-polymer PAGs (physically associating gels).

    Dynamic pressure, which drives bullet expansion and plays a role in determining the maximum penetration depth of bullets tested in it, is lower in Clear Ballistics Gelatin (which uses a urethane based elastomer and a plasticizer; a paraffinic oil) than it is in the two other acceptable test media, 10% ordnance gelatin and water because the density of Clear Ballistics Gelatin, approximately 865 kg/m3

    For example, if we take a hypothetical JHP moving at 1,250 fps (381 m/s) through water and 10% gelatin, we get the following pressure values that drive the expansion of our hypothetical JHP-

    For water: Pressure = ½ρTV2 = ½ x 999.972 kg/m3 x (381 m/s)2 = 72,578,467.75 N/m2

    For 10% gelatin: Pressure = ½ρTV2 = ½ x 1,040 kg/m3 x (381 m/s)2 = 75,483,720.0 N/m2

    which is very close indeed.

    However, contrasting these computed values with those derived in Clear Ballistics Gelatin, we see that the peak dynamic pressure produced in Clear Ballistics Gelatin is much less than (83.2% less) that seen in 10% ordnance gelatin-

    For Clear Ballistics Gelatin: Pressure = ½ρTV2 = ½ x 865 kg/m3 x (381 m/s)2 = 62,782,132.5 N/m2

    This decreased dynamic pressure translates to less bullet expansion and increased penetration depths for any given test arrangement in Clear Ballistics Gelatin.

    The relationship between test results obtained in Clear Ballistics Gelatin and the other two valid test mediums is non-linear, which means that a simple conversion factor does not exist.
    Despite the manufacturer's claims found here: ( https://www.clearballistics.com/faq/ ) ―

    Does your product replace ballistic gelatin used for testing ballistic data?

    ''Yes, it replaces traditional ordnance 240A ballistic gelatin 100%. Our product meets the FBI and NATO protocol for testing terminal ballistics of human tissue.''

    What is the FBI protocol you follow for calibrating ballistic gelatin?


    The FBI protocol we follow is firing a standard .177 caliber (4.5 mm) steel BB from an air gun over a chronograph at 590 feet per second (fps), plus or minus +/- 15 fps into the ballistic gelatin. The penetration of the steel BB must result in 8.5 centimeters (cm), plus or minus 1 cm, penetration (2.95 inches to 3.74 inches).
    ― Clear Ballistics Gelatin always fails to meet even the most basic standard for BB validation as a terminal ballistic test medium. Since it cannot rise to meet that elemental standard, Clear Ballistics Gelatin is of little value if one wants to obtain test results that are directly comparable to those obtained in proven/correlated soft tissue surrogates (10% gelatin, water). No statistical approach is going to change that fact.
    Last edited by the Schwartz; 03-08-2019 at 02:03 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.

  7. #227
    Site Supporter 0ddl0t's Avatar
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    Quote Originally Posted by the Schwartz View Post
    You've got this backwards
    Doh! You're right, thanks.

  8. #228
    Quote Originally Posted by 0ddl0t View Post
    Doh! You're right, thanks.
    Homer Simpson quotes?

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    ''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. #229
    DocGKR is there one 9mm ammo in your testing that was better than the rest? Did one bullet design stand out from the rest?
    Last edited by msciresa; 04-20-2019 at 11:44 AM.

  10. #230
    Anyone try the newest blazer brass flat point 147? I know AE 147 replicates HST well, but I found the blazer a bit cheaper. Fps was the same as AE 147. Thanks

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