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


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Brass Fetcher
October 24, 2011, 03:13 AM
Calibers : .22LR, .32ACP, .380ACP, 9x19mm, .40S&W, .45ACP, .357 Magnum, .44 Magnum JHPs, 22 K-Hornet, 223 Remington, 260 Remington, 308 Winchester and 30-06 Springfield

Were fired into 20% ballistic gelatin and the temporary cavity diameter and expansion velocity/KE were measured and presented in the report.

http://www.thehighroad.org/attachment.php?attachmentid=151448&stc=1&d=1319440372

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Inebriated
October 24, 2011, 03:39 AM
If I read that info right (skimmed over the graphs), the heavier bullets created substantially less of a stretch cavity? Very interesting.

ATLDave
October 24, 2011, 10:13 AM
Inebriated, isn't that what one would expect? That has always been the argument advanced by the light-and-fast advocates.

shadow9
October 24, 2011, 10:51 AM
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...

FIVETWOSEVEN
October 24, 2011, 12:32 PM
Why is it 20% instead of 10%?

Skribs
October 24, 2011, 12:57 PM
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.

Brass Fetcher
October 24, 2011, 01:54 PM
20% is the standard gelatin for high speed video.

Inebriated
October 24, 2011, 02:10 PM
Inebriated, isn't that what one would expect? That has always been the argument advanced by the light-and-fast advocates.


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.

mavracer
October 24, 2011, 02:12 PM
TWC means little unless the bullet is going over 2000 FPS, anyway.
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.

Skribs
October 24, 2011, 02:29 PM
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.

20% is the standard gelatin for high speed video.

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?

FIVETWOSEVEN
October 24, 2011, 03:20 PM
20% is the standard gelatin for high speed video.

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

mavracer
October 24, 2011, 03:28 PM
[QUOTE]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./QUOTE]
Sorry I just get tired of the 2000fps rule that Fackler basicly pulled out of his butt taken for fact. when the fact is as this study shows it starts to be a factor well below 2000fps.
If it didn't matter a 38 special FBI load would have the same wounding effect as a 125gr 357 @ 1450fps. I can tell you from personal experiance this just isn't the case. sure sometimes the critter reacts the same, but sometimes the 357 has a dramaticly different effect. As for the human factor thats a vairiable that can't be accounted for, but I assure once the blood pressure =0 it won't matter anymore and more damage will get the blood pressure to 0 faster.

Skribs
October 24, 2011, 03:47 PM
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.

If it didn't matter a 38 special FBI load would have the same wounding effect as a 125gr 357 @ 1450fps

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

mavracer
October 24, 2011, 04:37 PM
the difference in what human tissue can withstand vs. what a squirrel or an elephant can withstand. compairison to a squirrel or elephant would be a little extreme, with 200 pound animals there isn't that much difference.
Don't they both put a 9mm hole in the target?
Yes they both'll do that but for much of the wound track the 357 will have far more brusing and tearing.

gvf
October 24, 2011, 06:16 PM
Calibers : .22LR, .32ACP, .380ACP, 9x19mm, .40S&W, .45ACP, .357 Magnum, .44 Magnum JHPs, 22 K-Hornet, 223 Remington, 260 Remington, 308 Winchester and 30-06 Springfield

Were fired into 20% ballistic gelatin and the temporary cavity diameter and expansion velocity/KE were measured and presented in the report.

http://www.thehighroad.org/attachment.php?attachmentid=151448&stc=1&d=1319440372
This link is in Revolver forum. Many rounds shown in action:

http://www.brassfetcher.com/index_files/Page1950.htm

Brass Fetcher
October 25, 2011, 11:27 AM
FBI uses 10% and I don't remember seeing 20% anywhere else.

Browse through the (growing) Recommended Reading section : http://www.brassfetcher.com/index_files/Page3207.htm

20% gelatin has been in use since at least 1931.

mavracer
October 25, 2011, 12:16 PM
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.

MCgunner
October 25, 2011, 08:42 PM
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.

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

Brass Fetcher
October 26, 2011, 02:30 PM
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.

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" ... ;).

gvf
October 27, 2011, 06:28 PM
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.

ATLDave
October 27, 2011, 07:05 PM
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.

mavracer
October 27, 2011, 07:18 PM
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.
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
It was found that the magnitude of kinetic energy present at any point during the expansion was directly attributable to the initial velocity of the projectile at impact.
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.

FIVETWOSEVEN
October 27, 2011, 09:28 PM
20% gelatin has been in use since at least 1931.

But why does the FBI base their testing off of 10%?

Vern Humphrey
October 27, 2011, 09:39 PM
It's a perfect study -- perfect studies end with "Further study is indicated."

mavracer
October 27, 2011, 09:48 PM
But why does the FBI base their testing off of 10%?
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.

Brass Fetcher
October 28, 2011, 09:09 PM
It's a perfect study -- perfect studies end with "Further study is indicated."

Beautiful ... :). It would be nice to do a more exhaustive study on this subject ... we can (and have been recently) setting up the high speed video so that the TC can be accurately measured. This is in addition to measuring the primary effects like KE at depth or overall penetration, so it's a bit tricky to get all effects measurable on the same camera view.

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.

That, and also there are other benefits to 20% gelatin over 10%. One is the historical database - almost every shot done by western militaries since 1931 (at least) was done in 20% gelatin. So, if that data ever were made publicly available, the database could be expanded by the addition of repeatable private testing like ours in addition to being able to augment the testing by a comparison to past/similar results.

20% is also much more temperature stable - with 10% we calibrate the block 24hrs prior to the actual firearm being fired, refrigerate for 24hrs and then shoot. At room temperature, 'core' measurements on 10% usually goes up about 1 degree F every two minutes. Leave it out for about 10 minutes and the block is now out of spec for the next 24hrs. These problems exist to a much lesser extent with 20%.

gvf
October 29, 2011, 02:34 AM
Beautiful ... :). It would be nice to do a more exhaustive study on this subject ... we can (and have been recently) setting up the high speed video so that the TC can be accurately measured. This is in addition to measuring the primary effects like KE at depth or overall penetration, so it's a bit tricky to get all effects measurable on the same camera view.



That, and also there are other benefits to 20% gelatin over 10%. One is the historical database - almost every shot done by western militaries since 1931 (at least) was done in 20% gelatin. So, if that data ever were made publicly available, the database could be expanded by the addition of repeatable private testing like ours in addition to being able to augment the testing by a comparison to past/similar results.

20% is also much more temperature stable - with 10% we calibrate the block 24hrs prior to the actual firearm being fired, refrigerate for 24hrs and then shoot. At room temperature, 'core' measurements on 10% usually goes up about 1 degree F every two minutes. Leave it out for about 10 minutes and the block is now out of spec for the next 24hrs. These problems exist to a much lesser extent with 20%.
You'd have to read the whole FBI report. It didn't state that all shootings involve BGs who fall no matter how and where they are hit. Just that some do and it is therefore a factor found in the field relevant to the topic of handgun wounding and effectiveness. There are many others the report goes into as well. It is a comprehensive study.

And of course it's still your choice as to whether or not you believe it.

jaholder1971
October 29, 2011, 03:27 PM
This study further proves what we've all known...

Shot placement is everything.

VBVAGUY
October 29, 2011, 10:57 PM
I wonder how the .357Sig would have done ??? God Bless :)

Brass Fetcher
October 30, 2011, 01:05 AM
It should be very similar to the .357 Magnum.

If you enjoyed reading about "Report : Temporary Cavity Velocity for Pistol and Rifle projectiles in ballistic gel" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!