seeking ballistic gel test results with 147 gr loads from a glock 43

[oldtexan]

All, I did a search but was unable to find an answer to my question: Has anyone seen any proper ballistic gel testing with 147 gr 9mm loads ( particularly standard pressure HST) from a Glock 43, or from a different gun that could reasonably be expected to produce velocities similar to those from a 43? If so, did they consistently meet the standards when fired into either bare gelatin, or through FBI heavy clothing, or the IWBA 4 layer denim test? And how about the windshield test? Thanks in advance.

[TGS]

From the 2nd Page of DocGKR's 147gr Duty Load Testing thread (https://pistol-forum.com/showthread.php?20650-9-mm-147-gr-duty-load-testing), which is a "sticky" at the top of this sub-forum:


For 9 mm, the results are essentially identical with barrels from 3.5-5", you get more variation in lot to lot differences than with barrel length.

The G43 has a 3.4" barrel.

Take an educated guess whether its worth digging deeper.

[Shawn Dodson]

I chronographed 147gr HST (standard velocity) out of my G43 and measured 980 fps. (Yes, that's correct, 980 fps.)

[0ddl0t]

TNoutdoors9 did: https://m.youtube.com/watch?v=zYTd1lNx_TQ

[SWAT Lt.]

All, I did a search but was unable to find an answer to my question: Has anyone seen any proper ballistic gel testing with 147 gr 9mm loads ( particularly standard pressure HST) from a Glock 43, or from a different gun that could reasonably be expected to produce velocities similar to those from a 43? If so, did they consistently meet the standards when fired into either bare gelatin, or through FBI heavy clothing, or the IWBA 4 layer denim test? And how about the windshield test? Thanks in advance.

The standard pressure 147 HST should perform well out of your G43.

I asked a similar question to one of Vista Outdoors law enforcement sales guys at a corporate event a few months back. I asked him if one were to carry a short barreled gun, such as a G43, which ammo would he recommend. He smiled, pulled a loaded G43 magazine from his pocket, and said "these". I took the magazine and saw it was loaded with 147 HST standard pressure. The rep told me "they work pretty well out of shorter barreled guns". He has seen a great deal of ammunition testing and is aware of the actual performance in LE shootings of different types of Federal and Speer ammunition. He carries the 147 HST in his G43. DocGKR also carries the 147 HST. Good enough for me.

With this information plus everything I have learned and am seeing, I have pretty much standardized on the 147 HST across the board as my carny ammo.

[oldtexan]

The standard pressure 147 HST should perform well out of your G43.

I asked a similar question to one of Vista Outdoors law enforcement sales guys at a corporate event a few months back. I asked him if one were to carry a short barreled gun, such as a G43, which ammo would he recommend. He smiled, pulled a loaded G43 magazine from his pocket, and said "these". I took the magazine and saw it was loaded with 147 HST standard pressure. The rep told me "they work pretty well out of shorter barreled guns". He has seen a great deal of ammunition testing and is aware of the actual performance in LE shootings of different types of Federal and Speer ammunition. He carries the 147 HST in his G43. DocGKR also carries the 147 HST. Good enough for me.

With this information plus everything I have learned and am seeing, I have pretty much standardized on the 147 HST across the board as my carny ammo.

Thanks. That's what I've been looking for.

[Jeff S.]

Just to add to the good info above, here is another YouTube tester. He uses calibrated, ordinance gelatin, and he tests through both bare gel and four layers of heavy denim (albeit no safety glass). Testing using a 3” barrel. He loves the 147gr HST. Everybody talks about good ammo being barrier blind; it seems HST is also velocity blind.





https://m.youtube.com/watch?v=K3VfWkWMzOI&t=315s

[oldtexan]

Just to add to the good info above, here is another YouTube tester. He uses calibrated, ordinance gelatin, and he tests through both bare gel and four layers of heavy denim (albeit no safety glass). Testing using a 3” barrel. He loves the 147gr HST. Everybody talks about good ammo being barrier blind; it seems HST is also velocity blind.





https://m.youtube.com/watch?v=K3VfWkWMzOI&t=315s


Thanks.

[Lester Polfus]

Interesting. Over in a thread about revolvers in 9mm, I commented that I was unsure how 9mm loads with work out of a 2" LCR. A 3" auto-loader barrel is pretty much the same as a 2" revolver barrel, so perhaps this isn't as big a concern as I thought.

[SWAT Lt.]

I don't believe it is. I chronographed some rounds back when I had a S&W 940 as a BUG and I remember the velocities being pretty decent overall. IIRC, the 124 Hydra-Shok (our issued duty round at the time) averaged around 1050 fps. Federal advertises 1120 fps for this round but doesn't specify the type and length of barrel used. As many have noted in other threads, the 147 grain loadings lose less, percentage wise, than lighter bullets when fired from shorter barrels.

[Lester Polfus]

I don't believe it is. I chronographed some rounds back when I had a S&W 940 as a BUG and I remember the velocities being pretty decent overall. IIRC, the 124 Hydra-Shok (our issued duty round at the time) averaged around 1050 fps. Federal advertises 1120 fps for this round but doesn't specify the type and length of barrel used. As many have noted in other threads, the 147 grain loadings lose less, percentage wise, than lighter bullets when fired from shorter barrels.

Cool. I've already decided that my next j-frame will be an LCR, so I might just go ahead and get the 9mm.

[Buckeye63]

https://www.luckygunner.com/labs/self-defense-ammo-ballistic-tests/#9mm

This is a good link that has 9mm SD ammo ( some 147gr) tested out of a S&W compact

[Tokarev]

More 147 HST info.

http://www.general-cartridge.com/blog/federal-9mm-147gr-hst-in-clear-ballistics-gel

Sent from my SM-G930P using Tapatalk

[oldtexan]

More 147 HST info.

http://www.general-cartridge.com/blog/federal-9mm-147gr-hst-in-clear-ballistics-gel

Sent from my SM-G930P using Tapatalk

Thanks, Tokarev. Had never heard of that website before.

[Tokarev]

Thanks, Tokarev. Had never heard of that website before.That site is maintained by 5pins. He's a member here.

Sent from my SM-G930P using Tapatalk

[Navin Johnson]

Are there any LE/Military agencys that use "clear jell" to choose ammunition?

If not perhaps we shouldn't either?

[DocGKR]

No, there are not...

[medic15al]

No, there are not...

Doc, how do the two differ? clear gel too dense?

[JBP55]

Doc, how do the two differ? clear gel too dense?

Possibly the opposite, I see clear gel results that appear to be much better than the results listed by HST and Gold Dot on their website.

[DocGKR]

One has been correlated with living animal and human tissue; one has not.

[0ddl0t]

how do the two differ? clear gel too dense?


One has been correlated with living animal and human tissue; one has not.

Here is a comparison of typical defensive handgun speed projectiles. In it, clear gel is very highly correlated with organic gel:
https://m.youtube.com/watch?v=1kjcoFaobeo

Here is another test, but the clear gel was not properly calibrated:
https://m.youtube.com/watch?feature=youtu.be&v=KizfONaOVV0

The results diverge as you start getting into rifle type velocities:
https://youtu.be/KizfONaOVV0

[medic15al]

Here is a comparison of typical defensive handgun speed projectiles. In it, clear gel is very highly correlated with organic gel:
https://m.youtube.com/watch?v=1kjcoFaobeo

Here is another test, but the clear gel was not properly calibrated:
https://m.youtube.com/watch?feature=youtu.be&v=KizfONaOVV0

The results diverge as you start getting into rifle type velocities:
https://youtu.be/KizfONaOVV0

I really appreciate the info. Thanks!

I was curious as to why the bullets looked about the same but kept hearing there are discrepancies in performace.

[Navin Johnson]

I really appreciate the info. Thanks!

I was curious as to why the bullets looked about the same but kept hearing there are discrepancies in performace.

So again....what LE/Military organization uses "Shootingthebull410's" data for ammunition selection?

[DocGKR]

"In it, clear gel is very highly correlated with organic gel"

No, it is not.

"I was curious as to why the bullets looked about the same but kept hearing there are discrepancies in performace (sic)."

About the same, is not the same; there are in fact problems that prevent the synthetic gel from providing useful data--hence why NO professional ballistics facilities use it for testing (although the synthetic gels can be useful backers for armor testing).

[0ddl0t]

"In it, clear gel is very highly correlated with organic gel"

No, it is not.
Did you watch the video?

.................................................. ....OG......................CB
.45 acp 230gr hst +p 4.6"bbl.......0.841, 13.25......0.756, 14.0
.45 acp 185gr hcd 3.3" bbl...........0.667, 11.5.......0.635, 11.5
.45 lc 165gr hcd 2" bbl.................0.662, 11.25.....0.617, 12.5
.380 acp 90gr gd 3.5" bbl............0.530, 9.0.........0.515, 9.5
22lr 30gr as 3.5" bbl.....................0.357, 9.0.........0.350, 9.5
.410 360gr # 00bs 6.5" bbl...........0.40, 17.5.........0.40, 17.6
.410 180gr # 4bs 6.5" bbl.............0.24, 10.4.........0.24, 10.5

Pearson Correlation Coefficients:
Expansion (excluding buckshot): 0.9972 (R^2 .9944)
Expansion (including buckshot): 0.9979 (R^2 .9958)
Penetration: 0.9944 (R^2 .9888)


[x] highly correlated

Again, that is for fairly conventional defensive ammo at conventional handgun speeds using clear ballistics gel that has been verified to fall within FBI penetration specs for a 590fps .177bb

[DocGKR]

I most certainly did.

I also participated in the Joint Service Wound Ballistic Team where all terminal ballistic test formats (including test media, computer modeling, static vs. dynamic methods, etc...) were assessed to determine which best replicated the actual damage patterns seen in living tissue. When the JSWB-IPT analyzed this information in aggregate, the test protocol that was found to most closely correlate with actual shooting results and became the agreed upon JSWB-IPT “standard” evolved from the one first developed by Dr. Fackler at LAIR in the 1980’s, promoted by the IWBA in the 1990’s, and used by most reputable wound ballistic researchers--static 10% gel testing.

Looking at hobby videos with a few test shots does not equal laboratory testing with over 10,000 test shots.

Of course you are free to rely on any method you want and can choose to believe whatever you feel like...

For more information, please review: https://pistol-forum.com/showthread.php?32530-Predictive-tests-in-water/page2

[0ddl0t]

Looking at hobby videos with a few test shots does not equal laboratory testing with over 10,000 test shots.

Of course you are free to rely on any method you want and can choose to believe whatever you feel like...

For more information, please review: https://pistol-forum.com/showthread.php?32530-Predictive-tests-in-water/page2

I merely pointed out that within some reasonable constraints (typical handgun velocities, conventional types of ammunition), the results in calibrated clear gel have a very high mathematical correlation to the results in ordinance gel. And by "results" I mean whether the expansion and penetration meet FBI & IWBA specs. Your own post in the above link seems to concur:

Perma-gel and other synthetic polymer simulants can provide a reasonable result for bullet penetration and expansion, but under-represent bullet yaw, fragmentation, and stretch effects.

Clear gel simulates something that simulates something else. It is a copy of a copy and as such, some finer details get lost. But it is so much easier and more cost effective to work with, it makes a fantastic screener to weed out obviously unacceptable defensive handgun ammunition (something I find particularly useful when dealing with short barreled pocket pistols which often fail to properly expand highly regarded duty ammo, especially through heavy denim).

If after screening you then want to split hairs over which of the top performers is best (or of you want to test some new unconventional wonder ammo), by all means bring out the 250A.

[DocGKR]

If one is going to go to the time and expense to test, it makes more sense to do it right and get good data which can be compared with the vast quantity of information collected over the past 30 years rather than doing a mediocre attempt which looks pretty, but is not as accurate or useful...

[the Schwartz]

I merely pointed out that within some reasonable constraints (typical handgun velocities, conventional types of ammunition), the results in calibrated clear gel have a very high mathematical correlation to the results in ordinance gel. And by "results" I mean whether the expansion and penetration meet FBI & IWBA specs. Your own post in the above link seems to concur:


Clear gel simulates something that simulates something else. It is a copy of a copy and as such, some finer details get lost. But it is so much easier and more cost effective to work with, it makes a fantastic screener to weed out obviously unacceptable defensive handgun ammunition (something I find particularly useful when dealing with short barreled pocket pistols which often fail to properly expand highly regarded duty ammo, especially through heavy denim).

If after screening you then want to split hairs over which of the top performers is best (or of you want to test some new unconventional wonder ammo), by all means bring out the 250A.

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.

[Ed L]

I merely pointed out that within some reasonable constraints (typical handgun velocities, conventional types of ammunition), the results in calibrated clear gel have a very high mathematical correlation to the results in ordinance gel. And by "results" I mean whether the expansion and penetration meet FBI & IWBA specs. Your own post in the above link seems to concur:

Clear gel simulates something that simulates something else. It is a copy of a copy and as such, some finer details get lost. But it is so much easier and more cost effective to work with, it makes a fantastic screener to weed out obviously unacceptable defensive handgun ammunition (something I find particularly useful when dealing with short barreled pocket pistols which often fail to properly expand highly regarded duty ammo, especially through heavy denim).

If after screening you then want to split hairs over which of the top performers is best (or of you want to test some new unconventional wonder ammo), by all means bring out the 250A.

You do realize that you are lecturing one of the top wound ballistic experts in the business.

[0ddl0t]

You do realize that you are lecturing one of the top wound ballistic experts in the business.

I am not persuaded by appeals to authority when easily verifiable math does not support the assertion.

But for what its worth, I find the presumed pressure differentials intriguing. The shape of the projectile should affect localized pressures so it would be fascinating to see the pressure modeling for various cavity shapes (something I would expect to play a much, much greater role in expansion than a 17% difference in the medium's density). I wonder if I could get solidworks to model deformation/expansion...

[the Schwartz]

I am not persuaded by appeals to authority when easily verifiable math does not support the assertion.

But for what its worth, I find the presumed pressure differentials intriguing. The shape of the projectile should affect localized pressures so it would be fascinating to see the pressure modeling for various cavity shapes (something I would expect to play a much, much greater role in expansion than a 17% difference in the medium's density). I wonder if I could get solidworks to model deformation/expansion...

That sounds like an awful lot of work just to model the hydrodynamic flow phase (expansion) of the JHP when you could just test the whole penetration event in 10% ordnance gelatin or water and get the whole picture. You could also give ANSYS a try...

I suppose that you could also modify the Bernoulli pressure equation with the projectile's CD to try to obtain the surface-boundary pressure for a given design....

...or go even farther using the modifications to Bernoulli as suggested by Alekseevskii & Tate. (1967, 1969):

½ρ(V-U)2 + YP = ½ρU2 + RT where U may be assumed to be equal to Vo ÷ [1 + √(ρT ÷ ρP)]

The A-T projectile/target pressure interface (U and RT) relationship introduces some computational complication (calculus) into the process, but with that complication (which is mainly in accurately determining the value of RT, which is dependent upon impact velocity) comes some insight, too.

[Ed L]

I am not persuaded by appeals to authority when easily verifiable math does not support the assertion.

But for what its worth, I find the presumed pressure differentials intriguing. The shape of the projectile should affect localized pressures so it would be fascinating to see the pressure modeling for various cavity shapes (something I would expect to play a much, much greater role in expansion than a 17% difference in the medium's density). I wonder if I could get solidworks to model deformation/expansion...

Oh, you will do well here.

May I inquire about your background and experience?

Have you worked in wound ballistics or in a trauma center?

How many people have you treated who were shot in the face?

Can you detail the military, LEO and government wound ballistics projects that you have worked on?

Here is some of DrGKR's background:

"Dr. Roberts is currently on staff at Stanford University Medical Center; this is a large teaching hospital and Level I Trauma center were he performs hospital dentistry and surgery. After completing his residency at Navy Hospital Oakland in 1989 while on active military duty, he studied at the Army Wound Ballistic Research Laboratory at the Letterman Army Institute of Research and became one of the first members of the International Wound Ballistic Association. Since then, he has been tasked with performing military, law enforcement, and privately funded independent wound ballistic testing and analysis. He remains a Navy Reserve officer and has recently served on the Joint Service Wound Ballistic IPT, as well as being a consultant to the Joint FBI-USMC munitions testing program and the TSWG MURG program. He is frequently asked to provide wound ballistic technical assistance to numerous U.S. and allied SOF units and organizations. In addition, he is a technical advisor to the Association of Firearms and Toolmark Examiners, as well as to a variety of Federal, State, and municipal law enforcement agencies. He has been a sworn Reserve Police Officer in the San Francisco Bay Area, where he now he serves in an LE training role."

[PearTree]

It seems like every couple of months a blowhard comes in spouting stupidness. Doc comes in as always and politely tells them they have no clue what they are talking about and they start there blowharding even more and then leave pf altogether. DocGKR I am positive I speak for pf as a whole please disregard these people. We sincerely appreciate your knowledge and expertise and that you choose to participate here.

[GyroF-16]

DocGKR I am positive I speak for pf as a whole please disregard these people. We sincerely appreciate your knowledge and expertise and that you choose to participate here.

x2

We appreciate your patience, Doc, and really appreciate your input.

Please don’t let the guys who “don’t know what they don’t know” bring you down.

[Velo Dog]

Andrew's recent comparison of clear gel and 10% ballistic gel is worth watching. 10mm soft point needed an additional 200 fps to expand properly in clear gel.

https://www.youtube.com/watch?v=vRywrqRBfP4

[0ddl0t]

That sounds like an awful lot of work just to model the hydrodynamic flow phase (expansion) of the JHP when you could just test the whole penetration event in 10% ordnance gelatin or water and get the whole picture. You could also give ANSYS a try...
Yeah, a cursory investigation shows that this is beyond my capabilities with solidworks.

But if it could be done (and maybe ANSYS cfd could), you could test iterative designs far more rapidly than building a physical bullet and testing it in gel then redesigning & repeating. And who knows, the software visualizations might even help inform design improvements (e.g. number and shape of expanding petals).



I suppose that you could also modify the Bernoulli pressure equation with the projectile's CD to try to obtain the surface-boundary pressure for a given design....

...or go even farther using the modifications to Bernoulli as suggested by Alekseevskii & Tate. (1967, 1969):

½ρ(V-U)2 + YP = ½ρU2 + RT where U may be assumed to be equal to Vo ÷ [1 + √(ρT ÷ ρP)]

The A-T projectile/target pressure interface (U and RT) relationship introduces some computational complication (calculus) into the process, but with that complication (which is mainly in accurately determining the value of RT, which is dependent upon impact velocity) comes some insight, too.
If I was going to do it, I'd want to go far beyond the average pressure on a projectile and look at the localized pressure differentials (the inside of a hollowpoint cavity has to have higher pressures than the outside in order to force the motion of the copper & lead petal). And when you start looking at that level of detail, bernoulli's assumptions begin to fall apart (e.g. you don't have a homogeneous medium, there will also be trapped air which will likely be moving at supersonic speeds in places). That brings you to Navier Stokes and all the associated computational issues. Might make a good grad school project for someone smarter than me.

I suppose if you had a high definition high speed camera and gelatin with evenly spaced dye particles you could measure the speed of gelatin at various places and from there calculate more localized pressures, but that would be extremely laborious for what would still be a course visualization.



May I inquire about your background and experience? The laws of physics don't care about my background, why should you? Appeals to authority are invitations to substitute someone else's thought for your own.


Andrew's recent comparison of clear gel and 10% ballistic gel is worth watching. 10mm soft point needed an additional 200 fps to expand properly in clear gel.

You will sometimes find similar discrepancies with things like 357 & 5.7x28 or even unusual configurations of 9x19. For instance 150gr HST doesn't reliably expand from 3" barrels in clear gel - sometimes it does, sometimes it doesn't...

Personally I find that kind of design... fragility?... unacceptable - especially since the intended target has tissue densities from 250-1750 kg/m^3. I imagine everyone here knows about the ISP "biker incident" where a leather-clad drunk fat perp was unsuccessfully shot something like 13 times with an early expanding 9mm round. It led go the development of the ISP +p+ load to ensure expansion...

[DocGKR]

"It led go the development of the ISP +p+ load to ensure expansion..."

Which still was not a great load, as it tended to demonstrate 20 to 40% failure to expand in denim testing and was less than ideal against intermediate barriers like auto windshields. I personally would not choose to use it given all the better options currently available. With the exception of the Barnes 115 gr XPB all copper projectile, in general, most 9 mm 115 gr loads of any pressure have demonstrated greater inconsistency, insufficient penetration, poor intermediate barrier capability, and failure to expand in denim testing than other 9mm bullets. For those individuals wanting to use lighter weight, supersonic 9 mm’s, I think a better alternative than the vast majority of 115 gr loads is to use the slightly heavier 124 to 127 gr bullets or the Barnes 115 gr all copper bullet.

[Ed L]

The laws of physics don't care about my background, why should you? Appeals to authority are invitations to substitute someone else's thought for your own.

Okay, so on one hand we have a world renown wound ballisticiian who "is currently on staff at Stanford University Medical Center; this is a large teaching hospital and Level I Trauma center were he performs hospital dentistry and surgery. After completing his residency at Navy Hospital Oakland in 1989 while on active military duty, he studied at the Army Wound Ballistic Research Laboratory at the Letterman Army Institute of Research and became one of the first members of the International Wound Ballistic Association. Since then, he has been tasked with performing military, law enforcement, and privately funded independent wound ballistic testing and analysis. He remains a Navy Reserve officer and has recently served on the Joint Service Wound Ballistic IPT, as well as being a consultant to the Joint FBI-USMC munitions testing program and the TSWG MURG program. He is frequently asked to provide wound ballistic technical assistance to numerous U.S. and allied SOF units and organizations. In addition, he is a technical advisor to the Association of Firearms and Toolmark Examiners, as well as to a variety of Federal, State, and municipal law enforcement agencies. He has been a sworn Reserve Police Officer in the San Francisco Bay Area, where he now he serves in an LE training role."

On the other hand we have an anonymous internet poster whose postings contradict said expert and is complaining about appeals to authority; whose claims of "physics" do not match up with the Subject Matter Expert's extensive first hand experience that when compared to ballistic gelatin a certain tissue simulant "One has been correlated with living animal and human tissue; one has not."

[0ddl0t]

This will be my last response to you. I probably should just let it go, but I object to your miscategorization of my prior posts:

On the other hand we have an anonymous internet poster whose postings contradict said expert and is complaining about appeals to authority; whose claims of "physics" do not match up with the Subject Matter Expert's extensive first hand experience that when compared to ballistic gelatin a certain tissue simulant "One has been correlated with living animal and human tissue; one has not."

I have no doubt that DocGKR knows more about wound ballistics than I ever will and I don't question any of the mechanics he's illuminated here. But he erroneously disputed my claim that the results of one video showed a high correlation between calibrated clear & organic gel. I backed up my claim with the relevant statistics in post #25. DocGKR did not dispute my numbers. As a world renown wound ballistician he undoubtedly has access to a much larger sample of data from which he could check correlation coefficients for expansion & penetration of standard low speed handgun ammo in calibrated clear & organic gel.

I'm right; he's smart. If he hasn't already, he'll come around. But petty disputes over this sort of minutiae are what make academia insufferable. He misused a statistical term on an informal internet message board; it is not a big deal worthy of this protracted discussion. Even professional statisticians are terrible statisticians - here's an anecdote from Daniel Kahneman's book, "Thinking Fast & Slow," where he discusses the time the authors of two statistics textbooks failed to correctly answer a basic stats question on sample size:


Amos told the class about an ongoing program of research at the University of Michigan that sought to answer this question: Are people good intuitive statisticians? We already knew that people are good intuitive grammarians: at age four a child effortlessly conforms to the rules of grammar as she speaks, although she has no idea that such rules exist. Do people have a similar intuitive feel for the basic principles of statistics? Amos reported that the answer was a qualified yes. We had a lively debate in the seminar and ultimately concluded that a qualified no was a better answer.

Amos and I enjoyed the exchange and concluded that intuitive statistics was an interesting topic and that it would be fun to explore it together. That Friday we met for lunch at Café Rimon, the favorite hangout of bohemians and professors in Jerusalem, and planned a study of the statistical intuitions of sophisticated researchers. We had concluded in the seminar that our own intuitions were deficient. In spite of years of teaching and using statistics, we had not developed an intuitive sense of the reliability of statistical results observed in small samples. Our subjective judgments were biased: we were far too willing to believe research findings based on inadequate evidence and prone to collect too few observations in our own research. The goal of our study was to examine whether other researchers suffered from the same affliction.

We prepared a survey that included realistic scenarios of statistical issues that arise in research. Amos collected the responses of a group of expert participants in a meeting of the Society of Mathematical Psychology, including the authors of two statistical textbooks.As expected, we found that our expert colleagues, like us, greatly exaggerated the likelihood that the original result of an experiment would be successfully replicated even with a small sample. They also gave very poor advice to a fictitious graduate student about the number of observations she needed to collect. Even statisticians were not good intuitive statisticians.

And since you seem hung up on resumes, Daniel Kahneman won the Nobel prize in Economics (despite being a psychologist). Among other things, the other man was the subject of the world's shortest IQ test (the sooner you realized Amos Tversky was smarter than you, the higher your IQ).

[Tokarev]

Andrew's recent comparison of clear gel and 10% ballistic gel is worth watching. 10mm soft point needed an additional 200 fps to expand properly in clear gel.

https://www.youtube.com/watch?v=vRywrqRBfP4


I've used both types of gel. The synthetic is "cheaper" in that it can be used several times. The organic is "easier" in that it isn't terribly hard to mix and make but it does take several days for the process.

Anyway, one thing that seems to be lacking in most (maybe all) of the synthetic tests is a mention of calibration. Are testers ignoring this component of testing or just not mentioning it?

I wonder if we'll see Andrew return to organic gel. He started out using it but switched to synthetic awhile ago.

Here's some additional info on one simulant over another:

http://www.brassfetcher.com/Synthetic%20Gelatin/Synthetic%20Gelatin.html

[Ed L]

I'm right; he's smart. If he hasn't already, he'll come around. But petty disputes over this sort of minutiae are what make academia insufferable. He misused a statistical term on an informal internet message board; it is not a big deal worthy of this protracted discussion. Even professional statisticians are terrible statisticians - here's an anecdote from Daniel Kahneman's book, "Thinking Fast & Slow," where he discusses the time the authors of two statistics textbooks failed to correctly answer a basic stats question on sample size:

And does this alleged misuse of a statistical term somehow invalidate his vast professional experience?



And since you seem hung up on resumes, Daniel Kahneman won the Nobel prize in Economics (despite being a psychologist). Among other things, the other man was the subject of the world's shortest IQ test (the sooner you realized Amos Tversky was smarter than you, the higher your IQ).

Your anecdote is irrelevant to the discussion at hand--an attempted redirection or an evasion.

[the Schwartz]

If I was going to do it, I'd want to go far beyond the average pressure on a projectile and look at the localized pressure differentials (the inside of a hollowpoint cavity has to have higher pressures than the outside in order to force the motion of the copper & lead petal). And when you start looking at that level of detail, bernoulli's assumptions begin to fall apart (e.g. you don't have a homogeneous medium, there will also be trapped air which will likely be moving at supersonic speeds in places). That brings you to Navier Stokes and all the associated computational issues. Might make a good grad school project for someone smarter than me.

I suppose if you had a high definition high speed camera and gelatin with evenly spaced dye particles you could measure the speed of gelatin at various places and from there calculate more localized pressures, but that would be extremely laborious for what would still be a course visualization.

For that, you could also use SPH (smoothed particle hydrodynamics) which is a mesh-free particle method based on Lagrangian formulations capable of resolving partial differential equations such as the Navier-Stokes (N-S) equations that you cite. I've relied in the past on my present employer's ANSYS license to run SPH for similar problems and it has provided a tremendous depth of insight for the modeling that I find most fascinating.

[the Schwartz]

I've used both types of gel. The synthetic is "cheaper" in that it can be used several times. The organic is "easier" in that it isn't terribly hard to mix and make but it does take several days for the process.

Anyway, one thing that seems to be lacking in most (maybe all) of the synthetic tests is a mention of calibration. Are testers ignoring this component of testing or just not mentioning it?

I wonder if we'll see Andrew return to organic gel. He started out using it but switched to synthetic awhile ago.

Here's some additional info on one simulant over another:

http://www.brassfetcher.com/Synthetic%20Gelatin/Synthetic%20Gelatin.html

I am glad that you brought this up.

I'd been intending to provide a link to that Brassfetcher video; it seems that most folks using the synthetic gels (PAGs) seem to 'gloss over' the issue of proper block validation and the fact that the PAGs (including Clear Ballistics Gelatin, ρ = 0.865 g/cm3) seem to be woefully inadequate in satisfying that basic standard. I suspect that the main cause of this deficient performance is the significantly lower density of the most commonly employed synthetic analogs (0.830 g/cm3 -0.920g/cm3) as mass density has a significant influence upon the forces that act upon penetrating projectiles (namely, projectile expansion and deceleration).

Some research has been undertaken in how these PAGs behave, but they still fall short of the mark when it comes to replicating material/physical properties of human tissue: https://www.arl.army.mil/arlreports/2006/ARL-RP-134.pdf

Of course, PAGs have the benefit of offering the amateur hobbyist (as alluded to by Dr. Roberts in an earlier post) a less burdensome option because the synthetic gels are easier to work with and do not require the strict (thermal) controls that 10% concentration ordnance gelatin does. Water as a tissue simulant is always an option too, but as noted elsewhere in this subforum (by Dr. Roberts), it does not permit the capture and analysis of permanent and temporary cavity effects or the projectile's maximum penetration depth―unless we use a modified Poncelet penetration equation―without the use of mathematical models which might also be just as discouraging (to the casual hobbyist) as attempting to satisfy the technical burden of using 10% gelatin.

Andrew's work has always impressed me; I hope that he resumes using organic ordnance gel sooner rather than later.

[the Schwartz]

For everyone's consideration, here is direct link to the Brassfetcher video that I mentioned above that ties in with the link to the Brassfetcher website that was provided by Tokarev―

Tabular data relating to Clear Ballistic Gel's failure to meet the BB validation process can be found at 18:44 in the video. The penetration differential between 10% gelatin and Clear Ballistics Gel is glaring (found at 14:48 in video) and suggests that there is no simple (or accurate) conversion formula or factor for converting CBG data to its equivalent in calibrated 10% ordnance gelatin.


https://www.youtube.com/watch?v=5pqPBnSYTIc

[luckyman]

For everyone's consideration, here is direct link to the Brassfetcher video that I mentioned above that ties in with the link to the Brassfetcher website that was provided by Tokarev―

Tabular data relating to Clear Ballistic Gel's failure to meet the BB validation process can be found at 18:44 in the video. The penetration differential between 10% gelatin and Clear Ballistics Gel is glaring (found at 14:48 in video) and suggests that there is no simple (or accurate) conversion formula or factor for converting CBG data to its equivalent in calibrated 10% ordnance gelatin.


https://www.youtube.com/watch?v=5pqPBnSYTIc

Aannnnnd this is why I love PF. Thanks tS.

[Tokarev]

Something I've noted with the Clear Ballistics blocks I've purchased; they come with a little piece of cardboard that says the block was calibrated but there's no evidence of a BB ever being in the block. I can only guess that CB must calibrate a sample out of an entire production batch.

Sent from my SM-G930P using Tapatalk

[the Schwartz]

Something I've noted with the Clear Ballistics blocks I've purchased; they come with a little piece of cardboard that says the block was calibrated but there's no evidence of a BB ever being in the block. I can only guess that CB must calibrate a sample out of an entire production batch.

Sent from my SM-G930P using Tapatalk

That's interesting and kind of a surprise to me especially since the manufacturer states on the website ''FAQ'' page here―

https://www.clearballistics.com/faq/

that―


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.''

If the manufacturer is making such claim, and expects that their customer(s) should regard their product as being technically accurate and valid, it'd make sense to have that 'proof' (that is, the BB validation) present for their customers to see as evidence of an existing QC/QA program. I think that'd lend significant support to their claim that the product does meet that specification, as well as customers' satisfaction that they are using a valid test medium. At $130 (+ tax?) for a 6''x6''x16 block, it is not exactly what I'd call inexpensive. I'd imagine that for that price, those using it would want a product that accurately represents and matches terminal performance in 10% ordnance gelatin.

[0ddl0t]

Tabular data relating to Clear Ballistic Gel's failure to meet the BB validation process can be found at 18:44 in the video. The penetration differential between 10% gelatin and Clear Ballistics Gel is glaring (found at 14:48 in video) and suggests that there is no simple (or accurate) conversion formula or factor for converting CBG data to its equivalent in calibrated 10% ordnance gelatin.


Does anyone have Duncan MacPherson's bb calibration correction formula and know his boundary conditions? I see references to a figure 5-2 from his book "Bullet Penetration" where he supposedly corrects for up to +/- 2 inches of bb calibration, but I haven't seen the info directly. Is it just linear?


Raw data:
cal....OG...CB
.380 7.7 11.9
9mm 13.9 18.7
357s 14.8 15.3
12gs 12.5 16.5
12g#4 11.75 12.66

Pearson Correlation Coefficient: 0.7382 (moderate correlation)

35653

Assuming the blocks are numbered in the order shown in the graphs, if I use a linear correction to make the bb calibration 3.35" I get:
cal....OG...CB
.380 7.6 9.6
9mm 13.7 13.4
357s 15.0 13.2
12gs 11.9 13.3
12g#4 11.6 11.0

Pearson Correlation Coefficient: 0.8742 (moderate-high correlation)

[the Schwartz]

Does anyone have Duncan MacPherson's bb calibration correction formula and know his boundary conditions? I see references to a figure 5-2 from his book "Bullet Penetration" where he supposedly corrects for up to +/- 2 inches of bb calibration, but I haven't seen the info directly. Is it just linear?


Raw data:
cal....OG...CB
.380 7.7 11.9
9mm 13.9 18.7
357s 14.8 15.3
12gs 12.5 16.5
12g#4 11.75 12.66

Pearson Correlation Coefficient: 0.7382 (moderate correlation)

35653

Assuming the blocks are numbered in the order shown in the graphs, if I use a linear correction to make the bb calibration 3.35" I get:
cal....OG...CB
.380 7.6 9.6
9mm 13.7 13.4
357s 15.0 13.2
12gs 11.9 13.3
12g#4 11.6 11.0

Pearson Correlation Coefficient: 0.8742 (moderate-high correlation)

While I do have MacPherson's book, out of respect for his copyright, I cannot publish here his correction equation, as I respect both the man and his work. As an author myself, I am kind of 'sensitive' about that kind of stuff. I'd recommend highly purchasing his book, if you have not done so, which is available in e-book form here: https://www.amazon.com/Bullet-Penetration-Modeling-Incapacitation-Resulting-ebook/dp/B00L7CSV7E/ref=sr_1_1?keywords=bullet+penetration&qid=1551368334&s=gateway&sr=8-1 (yes, I am actually recommending my competitor's book as it is an excellent and very technical treatment of the subject!)

The correction formula to which you refer applies only to temperature effects (viscosity, boundary) in 10% ordnance gelatin. It does not apply to other simulants (e.g.: synthetic PAGs) as is indicated by MacPherson on page 85 (see the first sentence of the second paragraph) and cannot be used to ''convert'' test data obtained in Clear Ballistics Gelatin to an ''equivalent'' in 10% concentration ordnance gelatin. Although MacPherson and I have both gone about modifying the Poncelet penetration equation in very different ways, in this case I agree with him that a simple temperature correction equation is not going to apply to the special case of an entirely different material. So, as it presently stands, I do not believe that there is a way to make a silk purse (10% gelatin) out of this particular sow's ear (Clear Ballistics Gelatin).

So far as the matter is concerned, I believe that this―


If one is going to go to the time and expense to test, it makes more sense to do it right and get good data which can be compared with the vast quantity of information collected over the past 30 years rather than doing a mediocre attempt which looks pretty, but is not as accurate or useful...

―is the best advice there is.

[DocGKR]

Thank you.....I try to be practical, factual, and evidence based in my pursuits.

[the Schwartz]

Thank you.....I try to be practical, factual, and evidence based in my pursuits.

You're welcome. Just keep doing what you're doing, Doc! :)

[Tokarev]

Here's one of Andrew's latest--posted March 1st.

Does this signal a return to organic gel? Curious about what medium he choses in the future.


https://www.youtube.com/watch?v=Z3-ot0PBT-E&feature=youtu.be

Sorry for the thread drift since this isn't 147 9mm related.

[the Schwartz]

Here's one of Andrew's latest--posted March 1st.

Does this signal a return to organic gel?

I sure hope so. Perhaps this is a harbinger of things to come?




https://www.youtube.com/watch?v=Z3-ot0PBT-E&feature=youtu.be

Sorry for the thread drift since this isn't 147 9mm related.

Nonetheless, an interesting and informative test. Thanks for posting it.

I did notice that there seems to be no BBs present in the test block he uses in the video which surprises me given Andrew's usual inclusion of that data (BB validation, penetration depth, velocity) in his test results.

Perhaps I am too prone to the picking of nits, but when I see what I hope are 'legitimate' tests conducted in 'real' 10% concentration porcine-derived ordnance gelatin, as I have become accustomed to seeing in his tests, and have come to expect to see at least four distinct elements, so that the results can be assessed in a reasonable manner;

1.) BB validation values (velocity, penetration, temperature, etc.)
2.) the presence of some sort of scalar reference along the 'expected' shot line (ruler, tape measure, etc.)
3.) some sensible representation of the test data (e.g.: average bullet expansion diameter, initial/retained mass, impact velocity, maximum penetration depth)
4.) In situ imagery of the test projectile in its position of rest at its maximum penetration depth as well as the entirety of the projectile's path along with the scalar reference, preferably from at least two different sides of the test block(s)

Typically, he meets most of these requirements under his ''The Chopping Block'' account, but since this is under the arfcom banner maybe they didn't specify anything so strict?

The other reason that I enjoy Andrew's testing (in 10% ordnance gelatin, that is) so much is that his test data typically 'confirms' well against the penetration models found in QAS.

In this case, his test data...

Max. Diameter: 0.769''
Min. Diameter: 0.517''
Avg. Diameter: 0.643''
Initial/Retained Mass: 125 gr./110.7 gr.
Avg. Impact Velocity: 2,493 fps
Penetration Depth: 15.4''

...when run through the Q-model, gives predicted penetration depths of:

15.07'' (using the bullet's initial mass)
13.35'' (using the bullet's retained mass)

...and when run through the mTHOR model, gives predicted penetration depths of:

17.94'' (using the bullet's initial mass)
15.89'' (using the bullet's retained mass)

Incidentally, when Andrew's test data is run through Duncan MacPherson's penetration model, the following predicted penetration depths result:

14.22'' (using the bullet's initial mass, which includes +2'' 'correction-value' for neck length)
12.83'' (using the bullet's retained mass, which includes +2'' 'correction-value' for neck length)

I hope that this is the beginning of many more such tests to come.

[Squib]

Ok so I'm confused.

Should we all just ignore clear gel tests if we're serious about choosing good defensive ammo?

If thats the case, is there a resource on the internet that has extensive tests on different loads we can see and that is worth our consideration?

[the Schwartz]

Ok so I'm confused.

Should we all just ignore clear gel tests if we're serious about choosing good defensive ammo?

If thats the case, is there a resource on the internet that has extensive tests on different loads we can see and that is worth our consideration?

To paraphrase Dr. Roberts here―


If one is going to go to the time and expense to test, it makes more sense to do it right and get good data which can be compared with the vast quantity of information collected over the past 30 years rather than doing a mediocre attempt which looks pretty, but is not as accurate or useful...

―''anything worth doing, is worth doing right''.

On page 1 (see posts #16 and #17) of this thread, Dr. Roberts confirms that no military or law-enforcement agencies are using Clear Ballistics Gel. There is a reason for that. Results obtained in Clear Ballistics Gel are comparable only with other data obtained in Clear Ballistics Gel. 10% ordnance gelatin, which has been researched and correlates strongly with porcine (thigh) muscle tissue which is/was used as a human tissue analog in terminal ballistic testing, is the current standard. Water can also be used as a test medium (with modified Poncelet penetration equations to predict maximum penetration depth), but it does not allow for the examination of temporary cavity effects.

As far as publicly available resources using correctly prepared 10% concentration ordnance gelatin to conduct such tests, they exist but they also are ''far and few between'' to the best of my knowledge.

One such example is Shawn Dodson's 'site, which is now committed to internet archival ''storage'' here:

http://web.archive.org/web/20120119005103/http://firearmstactical.com/

Some of the cartridges tested in 10% gelatin are a bit dated; just a caveat.

[Squib]

Is this http://brassfetcher.com/ a good place to find what I'm looking for?

I gotta admit, I'm less then a layman when it comes to the science behind this stuff, and as well have to admit, I'd been taken in by the clear gel tests.

[Navin Johnson]

Is this http://brassfetcher.com/ a good place to find what I'm looking for?

I gotta admit, I'm less then a layman when it comes to the science behind this stuff, and as well have to admit, I'd been taken in by the clear gel tests.


The above "stickies" is likely the best available information on the interweb. Real testing needs to be done by somebody with experience ....... and it is likely quite spendy.

Sometimes I'm baffled by the questions people ask when the information is just a couple of threads up.

[the Schwartz]

Is this http://brassfetcher.com/ a good place to find what I'm looking for?

I gotta admit, I'm less then a layman when it comes to the science behind this stuff, and as well have to admit, I'd been taken in by the clear gel tests.

Brassfetcher (John Ervin, Mech. Eng.) does quite a bit of testing using 10% ordnance gelatin; but also in 20% ordnance gelatin (a common NATO/military test standard), so make sure that you know what you are looking at. John's work with 10% gelatin is thorough and one of the few sources that I rely upon when I require such testing. His testing (usually) relies upon multiple test shots for a specific munition; I've used his services to obtain some of the correlative data that I have used in my work.

Two such examples can be found here:

https://pistol-forum.com/showthread.php?32530-Predictive-tests-in-water&p=774644&viewfull=1#post774644

https://pistol-forum.com/showthread.php?32530-Predictive-tests-in-water&p=774989&viewfull=1#post774989

Ervin always provides the critical data as outlined below:

1.) BB validation values (velocity, BB penetration depth, temperature, test block time out of refrigeration, etc.)
2.) the visible presence of some sort of scalar reference along the 'expected' shot line (graduated ruler, tape measure, etc.)
3.) organized, sensible representation of the test data (e.g.: average bullet expansion diameter, initial/retained mass, impact velocity, maximum penetration depth)
4.) In situ imagery of the test projectile in its position of rest/orientation at its maximum penetration depth as well as the entirety of the projectile's path along with the scalar reference, preferably from at least two different sides of the test block(s)

Often, Ervin provides graphical data/tables relating to velocity and energy decay as a function of instantaneous time and/or penetration depth and lots of excellent high frame-rate videography that shows bullet yaw and temporary cavity effects.

In short, Ervin's production is 'first rate'.

[Squib]

Thank you much, "The Schwartz".

:D