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Report : Temporary Cavity Velocity for Pistol and Rifle projectiles in ballistic gel

Discussion in 'Handguns: Autoloaders' started by Brass Fetcher, Oct 24, 2011.

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  1. Brass Fetcher

    Brass Fetcher Member

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  2. Inebriated

    Inebriated Member

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    If I read that info right (skimmed over the graphs), the heavier bullets created substantially less of a stretch cavity? Very interesting.
     
  3. ATLDave

    ATLDave Member

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    Inebriated, isn't that what one would expect? That has always been the argument advanced by the light-and-fast advocates.
     
  4. shadow9

    shadow9 Member

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    The heavier bullets travel slower but offer higher sectional density - less speed=less force to expand the bullet, plus more material to expand, plus more tendency to penetrate due to high SD....or that's a theory...that was some of the issue with the older 147gr 9mm's - they were designed for a MP5 barrel, and weren't packed with a good charge for a short pistol barrel...
     
  5. FIVETWOSEVEN

    FIVETWOSEVEN Member

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    Why is it 20% instead of 10%?
     
  6. Skribs

    Skribs Member

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    This seems more like a general discussion thing than a handguns: autoloaders thing to me. As such, I still don't really see a point or a conclusion to the statement. TWC means little unless the bullet is going over 2000 FPS, anyway.
     
  7. Brass Fetcher

    Brass Fetcher Member

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    20% is the standard gelatin for high speed video.
     
    Last edited: Oct 24, 2011
  8. Inebriated

    Inebriated Member

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    Well I just meant the drastic differences were surprising. I didn't expect to see that. I was always under the impression that while lighter and faster bullets did make a bigger stretch cavity, that it wasn't nearly as much a differences as people made it out to be.
     
  9. mavracer

    mavracer Member

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    So it just magicly matters at 2000, so at 3000 it should reach full effectiveness and that pig dad shot through the chest shouldn't have been able to run 200 yards like his 270 was a starter pistol.
    TWC should never be counted on, but that doesn't mean it doesn't exist and can't be a factor well below 2000.
     
  10. Skribs

    Skribs Member

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    I didn't say it was everything over 2000 FPS. It's just that everything that I've read says under 2000 it matters little. At least against a human. I don't hunt so I haven't looked at what it is for other animals.

    What does it mimic? I understood that 10% was the standard because it mimicked human flesh. Does 20% do anything except look cooler in high speed video?
     
  11. FIVETWOSEVEN

    FIVETWOSEVEN Member

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    FBI uses 10% and I don't remember seeing 20% anywhere else.
     
  12. mavracer

    mavracer Member

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  13. Skribs

    Skribs Member

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    Mav, I wasn't talking about the psychological factor, but rather the difference in what human tissue can withstand vs. what a squirrel or an elephant can withstand.

    Don't they both put a 9mm hole in the target?
     
  14. mavracer

    mavracer Member

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    compairison to a squirrel or elephant would be a little extreme, with 200 pound animals there isn't that much difference.
    Yes they both'll do that but for much of the wound track the 357 will have far more brusing and tearing.
     
  15. gvf

    gvf Member

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    This link is in Revolver forum. Many rounds shown in action:

    http://www.brassfetcher.com/index_files/Page1950.htm
     
  16. Brass Fetcher

    Brass Fetcher Member

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  17. mavracer

    mavracer Member

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    Thanks for the time and effort JE223.
    This goes a ways to explain why the old 125gr 357mag seemed to be the "hammer of thor" sometimes.
     
  18. MCgunner

    MCgunner Member

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    Fired out of a 4" or longer barrel. Heavier bullets work better in the .357 snubs.
     
  19. Brass Fetcher

    Brass Fetcher Member

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    You're welcome. The 'sometimes' part has to come strictly from the shot location - a near miss of the heart would matter, a hit to the bottom of the abdomen not so much for instance. Which is why we pitch the training solution long before concern about ammunition should come into play. But that said, caliber selection is extremely important (assuming that the training is not in any way neglected in favor of technology.)

    I'm surprised that no one has called me a communist yet, because the .40S&W wasn't revealed to be the 'Vishnu' round. Vishnu as in "the destroyer of worlds" ... ;).
     
  20. gvf

    gvf Member

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    Very Important Issue

    This is a very important factor to keep in mind. From the seminal FBI Document:
    U. S. Department of Justice
    Federal Bureau of Investigation
    HANDGUN WOUNDING FACTORS AND EFFECTIVENESS



    "Further, it appears that many people are predisposed to fall down when shot. This phenomenon is independent of caliber, bullet, or hit location, and is beyond the control of the shooter. It can only be proven in the act, not predicted. It requires only two factors to be effected: a shot and cognition of being shot by the target. Lacking either one, people are not at all predisposed to fall down and don’t. Given this predisposition, the choice of caliber and bullet is essentially irrelevant. People largely fall down when shot, and the apparent predisposition to do so exists with equal force among the good guys as among the bad. The causative factors are most likely psychological in origin. Thousands of books, movies and television shows have educated the general population that when shot, one is supposed to fall down."

    Here is the entire report you can download as a PDF file. It is from late 80s I believe.
     

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    Last edited: Oct 27, 2011
  21. ATLDave

    ATLDave Member

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    Yeah, the FBI interprets a lot of stuff as being a voluntary sit-down "choice." I have always wondered if some of the incidents they characterize as voluntary is not, instead, about as voluntary as the choice to quit breathing when you get punched in the solar plexus. There's no physical force that lasts for several seconds that causes your breathing mechanisms to go into spasm, nor is there a "wound" that would explain why you cannot physically breath. But the body's reaction to a non-permanent stimulus can be very non-voluntary (and has little to do with being "trained" by TV or movies) and powerful. I wonder if those who embrace the "bullets punch holes, nothing more" view are perhaps misreading some "shock"-type effects as being voluntary, when they are not.
     
  22. mavracer

    mavracer Member

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    Having shot full house 357s in near darkness without ear protection I believe "sometimes" it might work to stop a threat just because the threat doesn't want to be subjected to any more cannon fire. LOL and still not banking on anything when it comes to SD with handguns.

    I saw where you stated that
    I would think it would be even more directly attributed to kinetic energy of the round at impact. Velocity is a big factor in KE but in cases of larger differences in the weight of the projectile the signifigantly heavier and slightly slower round may have more KE and would likely produce more radial energy.
    I know it's only one example but the 185gr 45+p and the 124gr 9mm+p would seem to bear this out.
    also from this I would estimate that a 9mm 115gr +p+ load at 1350fps would just eek into the maybe range and that the better 10mm loads would be similar to the 357.
     
  23. FIVETWOSEVEN

    FIVETWOSEVEN Member

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    But why does the FBI base their testing off of 10%?
     
  24. Vern Humphrey

    Vern Humphrey Member

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    It's a perfect study -- perfect studies end with "Further study is indicated."
     
  25. mavracer

    mavracer Member

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    Because that's what they decided to use as a standard when testing penatration and expansion. You can test in 20% and convert results, but that's not even what JE223 is doing here he is using 20% as a material of a known density to calculate radial energy.
     
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