Ballistic gelatin comparisons: Part I

[0ddl0t]

So your claim is that 10% gel is only good within certain fps ranges?

No. My claim is that a bullet at the low end of the range of fps that expands in ordnance gel may well not expand in human tissue at that same fps.

How did you determine that?

A single local autopsy where the decedent was shot twice with gold dot 147s from a 3.1" shield at nearly point blank range. 1 went through and the other entered between ribs, went laterally through his chest hitting lung & heart, and was stopped by a rib. Shot placement did the job, but the bullet failed to expand despite having a good track record with a local department in duty weapons.

Subsequent research shows this particular combo of gun & ammo often fails to expand in clear gel, meat targets, melons, etc yet performs well in ordnance gel.

No, it isn't. The current FBI protocols have a proven correlation with real world OIS, with a hell of a lot bigger and more recent sample then 28 bullets from 30 years ago from the time the protocol was originally being developed.

Dogmatic reliance on *just* the FBI tests can leave you susceptible to adopting faulty ammo you later need to recall - like the G2 (the highest scoring round in FBI history)

Modeling terminal ballistic performance in human tissue is not as simple as firing bullets into a substance of a desired density and then concluding that the terminal behavior seen in that material corresponds with what occurs in a human body.

Exactly. Given the inconsistent composition of human bodies we should be looking at behaviors in multiple simulants.

Valid physical models, like 10% ordnance gelatin and water, have been shown through extensive research to correlate strongly with living tissue in terms of their material properties.

10% OG has been shown to correlate with the average properties of living tissues.

Modeling terminal ballistic performance in fluids/liquids requires more than matching density (ρ) to achieve dynamic equivalence with soft tissue. In order to properly represent terminal performance in soft tissue, the candidate fluid/liquid must also possess the same bulk modulus (K) and internal sonic velocity (c) which are all related to one another in the Newton-LaPlace formula— c = √(K/ρ)

The internal speed of sound in isopropyl "rubbing" alcohol, C₃H₈O, is c = 1,205 ms^-1, its density is ρ = 786 kg/m³ so by extension of the Newton-LaPlace formula, its bulk modulus is K = 1.141 GPa.

Compared to the respective values of c, ρ, and K in water, 10% ordnance gelatin, and human soft tissue—

H₂O: c = 1,497 ms^-1, ρ = 999.87 kg/m³, K = 2.24 GPa
10% ordnance gelatin: c = 1,494 ms^-1, ρ = 1,040.00 kg/m³, K = 2.32 GPa
Typical values for human soft tissue: c = 1,540 ms^-1, ρ = 1,020 kg/m³, K = 2.42 GPa

—isopropyl alcohol does not compare favorably with any of these materials' values and therefore is not an acceptable candidate fluid (mixed with water or by itself) for modeling terminal ballistic response as it occurs in human tissue. No such research suggesting otherwise exists.

Within reason (e.g. shooting water not ice), the properties that affect expansion are density & velocity. For this supplemental test I'm not interested in correlating penetration depth, just checking for a robust margin of expansion.

Given the lack of supporting research that "ensures the consistency" of any of the "different media" that you've suggested, their use is likely to yield dubious data at best. At worst, relying on that data leads to inaccurate, and possibly dangerous, conclusions being drawn about the ammunition tested in those uncorrelated mediums.

What danger exists in selecting ammunition that passes both the traditional FBI/IWBA tests and still shows valid expansion in alternative media?

[BehindBlueI's]

A single local autopsy where the decedent was shot twice with gold dot 147s from a 3.1" shield at nearly point blank range.

How did the Gold dot do in the entirety of the FBI protocol at the fps it was launched from the Shield?

Dogmatic reliance on *just* the FBI tests can leave you susceptible to adopting faulty ammo you later need to recall - like the G2 (the highest scoring round in FBI history)

Was that a problem with the test or a problem with unannounced changes/manufacturing errors with the ammunition?

[Duelist]

Modeling terminal ballistic performance in human tissue is not as simple as firing bullets into a substance of a desired density and then concluding that the terminal behavior seen in that material corresponds with what occurs in a human body. Valid physical models, like 10% ordnance gelatin and water, have been shown through extensive research to correlate strongly with living tissue in terms of their material properties. Since the desired objective is to accurately represent a projectile's terminal performance in human tissue, only those specific mediums that can be shown to demonstrate the correct physical properties are valid as a means of modeling such performance. Beyond considering only the mass density of a solid test medium, a solid must also demonstrate the correct shear response within the typical magnitude of strain rates observed in such testing. Data obtained from "different media" that you've suggested above such as butter, margarine, mozzarella cheese, and for that matter, fruits, vegetables, and deli-meats, are not "supplemental" at all; in fact, they are specious and lack evidence that supports their validity as a terminal ballistic test medium that correlates with human tissue.

The clear, synthetic gel product, with its frequent changes in composition and component sourcing, is also unsuitable not only for the undocumented changes in its formulation but also for the failure of the manufacturer(s) of these products to provide information on how these changes in composition and source compare against previous iterations of their product(s).

Modeling terminal ballistic performance in fluids/liquids requires more than matching density (ρ) to achieve dynamic equivalence with soft tissue. In order to properly represent terminal performance in soft tissue, the candidate fluid/liquid must also possess the same bulk modulus (K) and internal sonic velocity (c) which are all related to one another in the Newton-LaPlace formula— c = √(K/ρ)

The internal speed of sound in isopropyl "rubbing" alcohol, C₃H₈O, is c = 1,205 ms^-1, its density is ρ = 786 kg/m³ so by extension of the Newton-LaPlace formula, its bulk modulus is K = 1.141 GPa.

Compared to the respective values of c, ρ, and K in water, 10% ordnance gelatin, and human soft tissue—

H₂O: c = 1,497 ms^-1, ρ = 999.87 kg/m³, K = 2.24 GPa
10% ordnance gelatin: c = 1,494 ms^-1, ρ = 1,040.00 kg/m³, K = 2.32 GPa
Typical values for human soft tissue: c = 1,540 ms^-1, ρ = 1,020 kg/m³, K = 2.42 GPa

—isopropyl alcohol does not compare favorably with any of these materials' values and therefore is not an acceptable candidate fluid (mixed with water or by itself) for modeling terminal ballistic response as it occurs in human tissue. No such research suggesting otherwise exists.

Due to the frequent and unknown changes in its formulation, it is also difficult to ascertain values of c, ρ, and K of the clear, synthetic gel. The only physical property of the clear, synthetic gel that is known has been subject to some variance at different times within the same source ranging from 790 kg/m³ - 824 kg/m³ with no known values for either its internal sonic velocity or bulk modulus.

Given the lack of supporting research that "ensures the consistency" of any of the "different media" that you've suggested, their use is likely to yield dubious data at best. At worst, relying on that data leads to inaccurate, and possibly dangerous, conclusions being drawn about the ammunition tested in those uncorrelated mediums.

Science!

[0ddl0t]

How did the Gold dot do in the entirety of the FBI protocol at the fps it was launched from the Shield?

The Gold dot 147 (original, not g2) performs well in bare gel & through iwba 4ld from a 3.0" PM9.

Was that a problem with the test or a problem with unannounced changes/manufacturing errors with the ammunition?

Speer was tight lipped, but the G2 V2's skive and seating depth differences are more than a single manufacturing error.

Recalled G2:


Version 2 G2:

[the Schwartz]

Exactly. Given the inconsistent composition of human bodies we should be looking at behaviors in multiple simulants.

I don't know how else to say it, make it any clearer, or explain it any more clearly than I have. The fact that you have elected to ignore the underlying science that defines the physical material properties necessary for a substance to qualify as a valid terminal ballistic test medium suggests that you have either simply rejected it out of hand or don't understand its relevance or both. I've provided sourced, confirmable information describing the physical material properties of the two valid test mediums presently being used by labs across the nation. The information presented in my prior posts is open to analysis and review in support of the principle of dynamic equivalence being necessary in a test medium if it is to represent terminal ballistic performance of projectiles in human soft tissue. Unless you can substantiate the same physical material properties for any of the "different mediums" suggested in your prior posts—those being butter, margarine, mozzarella cheese, fruits, vegetables, and deli-meats—so that they can be compared directly to the respective values of c, ρ, and K for water, 10% ordnance gelatin, and human soft tissue, any suggestion that butter, margarine, mozzarella cheese, fruits, vegetables, and deli-meats are valid test mediums fails to stand on its own especially when they are subjected to examination under the same standard as the other human tissue simulants.

In other words, if you shoot a block of butter with a bullet that expands in it, it doesn't mean anything other than that the bullet expanded when it was fired into butter and in no way suggests that the same result can be expected of it if it is fired into human soft tissue. If you shoot a block of margarine with a bullet that expands in it, it doesn't mean anything other than that the bullet expanded when it was fired into margarine and in no way suggests that the same result can be expected of it if it is fired into human soft tissue. If you shoot a block of mozzarella cheese with a bullet that expands in it, it doesn't mean anything other than that the bullet expanded when it was fired into mozzarella cheese and in no way suggests that the same result can be expected of it if it is fired into human soft tissue.

Terminal ballistic testing in properly prepared 10% ordnance gelatin and water closely represents the response of the bullet that strikes human soft tissue.



None of the "different mediums" (butter, margarine, mozzarella cheese, fruits, vegetables, deli-meats) suggested in your prior posts can make that claim and are representative of nothing other than terminal ballistic performance in themselves. Ignoring these facts and underlying science does not validate these "different mediums".

[the Schwartz]

Modeling terminal ballistic performance in human tissue is not as simple as firing bullets into a substance of a desired density and then concluding that the terminal behavior seen in that material corresponds with what occurs in a human body. Valid physical models, like 10% ordnance gelatin and water, have been shown through extensive research to correlate strongly with living tissue in terms of their material properties. Since the desired objective is to accurately represent a projectile's terminal performance in human tissue, only those specific mediums that can be shown to demonstrate the correct physical properties are valid as a means of modeling such performance. Beyond considering only the mass density of a solid test medium, a solid must also demonstrate the correct shear response within the typical magnitude of strain rates observed in such testing. Data obtained from "different media" that you've suggested above such as butter, margarine, mozzarella cheese, and for that matter, fruits, vegetables, and deli-meats, are not "supplemental" at all; in fact, they are specious and lack evidence that supports their validity as a terminal ballistic test medium that correlates with human tissue.

The clear, synthetic gel product, with its frequent changes in composition and component sourcing, is also unsuitable not only for the undocumented changes in its formulation but also for the failure of the manufacturer(s) of these products to provide information on how these changes in composition and source compare against previous iterations of their product(s).

Modeling terminal ballistic performance in fluids/liquids requires more than matching density (ρ) to achieve dynamic equivalence with soft tissue. In order to properly represent terminal performance in soft tissue, the candidate fluid/liquid must also possess the same bulk modulus (K) and internal sonic velocity (c) which are all related to one another in the Newton-LaPlace formula— c = √(K/ρ)

The internal speed of sound in isopropyl "rubbing" alcohol, C₃H₈O, is c = 1,205 ms^-1, its density is ρ = 786 kg/m³ so by extension of the Newton-LaPlace formula, its bulk modulus is K = 1.141 GPa.

Compared to the respective values of c, ρ, and K in water, 10% ordnance gelatin, and human soft tissue—

H₂O: c = 1,497 ms^-1, ρ = 999.87 kg/m³, K = 2.24 GPa
10% ordnance gelatin: c = 1,494 ms^-1, ρ = 1,040.00 kg/m³, K = 2.32 GPa
Typical values for human soft tissue: c = 1,540 ms^-1, ρ = 1,020 kg/m³, K = 2.42 GPa

—isopropyl alcohol does not compare favorably with any of these materials' values and therefore is not an acceptable candidate fluid (mixed with water or by itself) for modeling terminal ballistic response as it occurs in human tissue. No such research suggesting otherwise exists.

Due to the frequent and unknown changes in its formulation, it is also difficult to ascertain values of c, ρ, and K of the clear, synthetic gel. The only physical property of the clear, synthetic gel that is known has been subject to some variance at different times within the same source ranging from 790 kg/m³ - 824 kg/m³ with no known values for either its internal sonic velocity or bulk modulus.

Given the lack of supporting research that "ensures the consistency" of any of the "different media" that you've suggested, their use is likely to yield dubious data at best. At worst, relying on that data leads to inaccurate, and possibly dangerous, conclusions being drawn about the ammunition tested in those uncorrelated mediums.

Science!

Exactly!

I am pleased and encouraged to see that there are P-F members here who have not discarded the scientific method in favor of baseless, unsupported opinion.

[BehindBlueI's]

The Gold dot 147 (original, not g2) performs well in bare gel & through iwba 4ld from a 3.0" PM9.

Which does not answer my question. There is a reason the FBI protocol is more than bare gel and 4LD.

I'll repeat, how did the Gold dot do in the entirety of the FBI protocol at the fps it was launched from the Shield?

Speer was tight lipped, but the G2 V2's skive and seating depth differences are more than a single manufacturing error.

So if a given bullet passes and then the bullet changes and doesn't fare well...what's that got to do with the validity of the test of the original bullet? Hint: Nothing.

[KellyinAvon]

If you do this, please post video. And make it vanilla pudding. I hate vanilla pudding so it's got it comin'.

I'm thinking they won't let me back on the range if I did that. It's two miles from the house, really convenient. I'm picturing a video played completely straight, "Please note I'm filling the authentic pinata with vanilla pudding. NOT INSTANT, this is real vanilla pudding I'm using as my ballistic material. My authentic pinata is from Wal-Mart and was made in China. My Winchester Model 1200 has a 26 inch barrel, is full choke, and kicks like a mule. The Hornady slugs are totally badass."

[0ddl0t]

We're starting to go round and round - I'll make these points one last time...

I don't know how else to say it, make it any clearer, or explain it any more clearly than I have. The fact that you have elected to ignore the underlying science that defines the physical material properties necessary for a substance to qualify as a valid terminal ballistic test medium suggests that you have either simply rejected it out of hand or don't understand its relevance or both.

I haven't, yet you continue to make this straw man case. I tried bolding the question last time in hopes you would address it, but let me try adding a larger font this time too:

What danger exists in selecting ammunition that passes both the traditional FBI/IWBA tests and still shows valid expansion in alternative media?

It seems to me the only danger is in acknowledging that the existing tests, which have more or less remained unchanged for 25 years, might not be so perfect (something that was readily acknowledged 25 years ago - and something that should be blatantly obvious now that the "highest scoring FBI round" is no longer being used by the FBI).

Terminal ballistic testing in properly prepared 10% ordnance gelatin and water correctly represents the response of the bullet that strikes human soft tissue.

If that were true we wouldn't have the heavy clothing and 4 layers of denim tests because water & 10% OG both overstate expansion seen in real life. Heavy clothing and denim obviously do not have comparable speeds of sound or bulk moduli to living tissue (nor do they represent reasonable clothing). Are you telling me their additions to FBI/IWBA protocols were not scientifically valid?

Which does not answer my question. There is a reason the FBI protocol is more than bare gel and 4LD.

I'll repeat, how did the Gold dot do in the entirety of the FBI protocol at the fps it was launched from the Shield?

I have not tested it, nor am I aware of anyone who has. I personally don't test through barriers I'm unlikely to encounter as a civilian.

So if a given bullet passes and then the bullet changes and doesn't fare well...what's that got to do with the validity of the test of the original bullet? Hint: Nothing.

Do you have evidence there was a change after the FBI tested it, but before it reached consumers? The recalled G2 still performed well from Glock 17s in 10% ordinance gel...

[the Schwartz]

Are you telling me their additions to FBI/IWBA protocols were not scientifically valid?

Nothing that I have said so far on this forum could ever—not even remotely—be construed in that way.

We're starting to go round and round - I'll make these points one last time...

I haven't, yet you continue to make this straw man case. I tried bolding the question last time in hopes you would address it, but let me try adding a larger font this time too:

What danger exists in selecting ammunition that passes both the traditional FBI/IWBA tests and still shows valid expansion in alternative media?

It seems to me the only danger is in acknowledging that the existing tests, which have more or less remained unchanged for 25 years, might not be so perfect (something that was readily acknowledged 25 years ago - and something that should be blatantly obvious now that the "highest scoring FBI round" is no longer being used by the FBI).

If that were true we wouldn't have the heavy clothing and 4 layers of denim tests because water & 10% OG both overstate expansion seen in real life. Heavy clothing and denim obviously do not have comparable speeds of sound or bulk moduli to living tissue (nor do they represent reasonable clothing). Are you telling me their additions to FBI/IWBA protocols were not scientifically valid?

I think that it might be wise for you to cool-off for a bit.