Discussion in 'Handguns: General Discussion' started by WoodchuckAssassin, Nov 8, 2020.
I said all rounds that pass testing are considered good to go. I never said they were equal.
I just reread this entire thread and at no point did I say 12-18" is all equal or anything like that. In fact the only time I brought up those two measurements was to explain in quick layman's terms why they were in the testing process. Other than that Ive stated that ammo that passes FBI testing is considered good for duty use and ammo that doesn't pass is considered not good for duty use. You are the on who has constantly put words in other people's mouths and are arguing points that no one in this thread have made.
Can anyone post information on how the rounds are scored by the FBI ?
This paper was a FBI bulletin from 1989. It goes over the testing pretty well but does not tell you the exact scoring method. Still pretty interesting.
Some of the testing has changed over the years from what I understand. A big one is the clothing material was changed to denim and/or fleece (Ive read both) instead of the down material.
I have read this thread several times and I still don’t understand mavracer’s point.
In order to have an objective test used to award millions of dollars worth of contracts one has to set parameters. A 12” penetration minimum is one of the parameters. Plain and simple. There are additional parameters and scoring values that the ammo manufacturers are fully aware of prior to submission of test ammo.
The FBI selects ammo based on the protocols identified so ammo companies can understand the criterion for selection. However, if a real world incident happens it can trump a duty ammo selection. For example, several agents got in a shootout with someone inside a car. The (then current) duty .45 ACP ammo failed miserably through the windshield but the .40 S&W duty ammo worked as expected. Almost the next day the duty .45 ACP ammo was yanked from the field and a bonded version was substituted instead. The initial knee-jerk reaction that almost transpired was to yank all .45 ACP sidearms completely. That came to pass with the selection of a 9mm sidearm as standard issue, and those .45s that were grandfathered eventually fall off of the list and can no longer be carried.
i wasn't able to find FBI referances to their scoring methodology but at Brassfetcher's site he has the information.
He certainly seemed knowledgeable about the FBI protocols and ballistics testing.
There seems to be a conflict between what has been written and how they actually score ammunition. The FBI used a scoring table for penetration. If they actually preferred deeper penetrating ammo then they should have given deeper penetrating ammo higher points. Instead point assignment drops off after 15.99 inches
Revisions to standard test:
Switch from Down to Polartec, January 1, 2004
The original test, created in 1988, used a down comforter (500-550 fill power) in a cambric shell (approx 232 threads per inch) as part of the heavy clothing mix. On January 1st, 2004, the protocol was changed to replace the down comforter with Polartec 200 fleece.
The switch to Polartec 200 was made in an effort to reduce uncontrollable variables in the test procedure and because fleece had become more prevalent than Down.
Down comforters typically consist of stitched baffles containing the down. As the comforter is laid in front of the gelatin block, it is not uncommon for down to migrate to the bottom of the panel. It was difficult, if not impossible, to ensure that each shot was subjected to the same amount of down. Prior to the switch, a comparison of bullet penetration, expansion and retained weight was conducted to see what, if any, changes would occur. Five shots were fired into a block of gelatin covered with the "down" heavy clothing and five shots were fired into a block of gelatin covered with the "fleece" heavy clothing. The validation numbers for the gelatin blocks were similar to ensure that the blocks were as identical as possible. Ten (10) cartridges, two (2) rifle and eight (8) handgun, were compared. The results showed that the penetration averages differed by .2" (a -0.8% change), the expansion differed by .01" (a 2.2% change) and the weight difference was negligible (a .5% change). Based on the testing conducted, it was determined that the consistency provided by a change to fleece would make the test protocol more scientifically repeatable and, therefore, provide better data for making ammunition selections.
1. You don't have to ignore anything to see that everything above 12" is acceptable. Acceptable is acceptable and 12" or more is acceptable per the protocol--without ignoring anything.
2. Not everything is equal. Different penetration ranges are scored differently. 12-14 gets one score, 14-16 gets the best score, 16-18 gets yet a different score and above 18 gets the lowest score of any range above 12"
JHP all the way. If it works as designed it's much superior and if it doesn't then you're still no worse off than with an FMJ.
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