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Thread: Question: "Muzzle Energy" vs. "Power Factor"

  1. #61
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    Quote Originally Posted by Todd.K View Post
    Bare gel or 4ld?
    Both bare gel and 4 layer denim.
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  2. #62
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    Quote Originally Posted by LimeSpoon View Post
    ... It also does not award any additional points for expansion over 0.625 inches, which potentially biases the test against certain bullets that can achieve well in excess of that...

    .
    Typical government testing, eh?

    Someone or group makes a decision then creates a "test" or "bid competition" to make it look honest knowing exactly what the result is GOING to be.

  3. #63
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    I'd wonder if the peculiarities going on with the .38 HP and 115 gr +P+ can be largely attributed to lot variation. This was kind of what I was going at with the mention of Gold Dot G2; it expanded consistently in FBI testing but often failed to mushroom when the first mass produced lots actually made it to the shelves. As I recall it was pulled from the commercial market and was not re-released until some time later.

    I think 230 gr Ranger-T may have had some of the same going on, at least in the past, though not nearly as bad. Its "standard" performance is pretty close to HST, but is not as consistent.

    Another possible contributor was that it was actually the FBI heavy clothing test being used for the 115 gr +P+, and not the more stringent IWBA 4LD test.

    Quote Originally Posted by Ron3 View Post
    Typical government testing, eh?

    Someone or group makes a decision then creates a "test" or "bid competition" to make it look honest knowing exactly what the result is GOING to be.
    While they may have changed the equation at some point, I believe the formula was composed back in the early 90s or so. To be fair, at the time, a bullet that averaged 0.625" across the 6 tests would have been very impressive.

    Still, the method of points assignment does seem questionable to me. I suspect that the significance of low variation in penetration across all barriers - which is, to some extent, independent of whether the bullet actually penetrates adequately - played a part in the selection of CD over HST. And the rather modest importance placed on very large expansion might have been used to support the FBI's assertion that modern 9mm loads are performing on par with modern .45 loads...looking at the bare gel, 4LD, and auto glass data, a person less restrained by this sort of boxed thinking might observe that 230 gr +P HST achieves similar penetration to 147 gr HST while affording approximately 60% more frontal area. But by the FBI equation, I would guess they score pretty much the same.

  4. #64
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    For the mathematically inclined, I chronographed the 9mm 115g HP +P+ using a pistol with a 4" barrel. Average Velocity at 15 feet from the muzzle was 1,340 fps.
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