Non-scientific hobbyist entertainment with synthetic gel.

[JCN]

Sure I am. It seems that you wish to have it both ways. Actual proof of concept in complex dynamic behavior like this requires many, many, many more data points than you have, or are likely to produce, in this endeavor. Either this is ''not scientific and for entertainment only!'' (like it is now) or this endeavor is an attempt to legitimately (that's science!) validate the linear and non-linear impact response dynamics of a material that has significant issues attributed to it through prior research.

OK, so at present you've got what? Five shots in each of three calibers in a very narrow velocity band for a total of 15?

So, there's one out of three. You're batting 0.333.

As was pointed out to you in post #46 of this thread by another poster, it is both velocity and expansion (size).

I've also made the point several times that since the Bernoulli equation which determines how/why dynamic pressure is produced (velocity and density), that because the density of the CBG stuff is less than that of water (which you even confirmed right here in this thread!), the CBG stuff is clearly incapable of matching the dynamic pressure (which drives projectile expansion) that the same projectile at the same velocity would encounter in actual 10% ordnance gelatin.

Answer me this please because you’ve danced around it and ignored it.

For your last point about density.

You’ve said that because of the lack of density, CBG won’t ever expand bullets as large as organic, correct?

But that’s not true.

Brass Fetcher tested HST 45 ACP out of 5 inch barrel.

Expanded 0.73



Shooting it into less dense gel…

I got 0.82…

So how is a less dense medium getting more expansion.



My explanation was that there’s more going on with the model than just density and the model is too simplistic with interactive, dynamic properties of the polymer coming into play.

Can you explain?

[the Schwartz]

Answer me this please because you’ve danced around it and ignored it.

For your last point about density.

You’ve said that because of the lack of density, CBG won’t ever expand bullets as large as organic, correct?

But that’s not true.

Brass Fetcher tested HST 45 ACP out of 5 inch barrel.

Expanded 0.73



Shooting it into less dense gel…

I got 0.82…

So how is a less dense medium getting more expansion.



My explanation was that there’s more going on with the model than just density and the model is too simplistic with interactive, dynamic properties of the polymer coming into play.

Can you explain?

Sure. It's called ''cherry-picking'' data to fit your narrative.

In the one case that you chose to illustrate your point, your CBG expansion value exceeded a data point (expansion) taken from Brassfetcher that does not provide actual test velocities, but rather factory specified velocities. You don't really know at what velocity BrasFetcher's test bullet hit the gelatin. Why?

Look at all of the velocities in that table that you cited. They're all perfect matches to the factory specified velocities of those loads.

When was the last time that you saw any gelatin test (of any type) in which the test bullets all matched exactly the factory spec velocity?

Brassfetcher's data presentation is a bit sloppy in that regard.

You've seized on a single data point that means less than nothing.

[JCN]

Sure. It's called ''cherry-picking'' data to fit your narrative.

In the one case that you chose to illustrate your point, your CBG expansion value exceeded a data point taken from Brassfetcher that does not provide actual test velocities, but rather factory specified velocities. You don't really know at what velocity BrasFetcher's test bullet hit the gelatin. Why?

Look at all of the velocities in that table that you cited. They're all perfect matches to the factory specified velocities of those loads.

When was the last time that you saw any gelatin test (of any type) in which the test bullets all matched exactly the factory spec velocity?

Brassfetcher's data presentation is a bit sloppy in that regard.

You've seized on a single data point that means less than nothing.

Well, I used the same barrel length that Brass Fetcher did.

So the velocity should be similar.

And I don’t think my 5” barrel is going to give 200fps higher velocity than his.

We call the data point “a clue.”

It’s not proof, but should very much bring out the possibility that there’s more than density at play.

You want things to “mean less than nothing” but that’s your bias to ignore everything except what you’re wanting to believe.

Prelim data then leads to confirmatory experiments. It doesn’t mean nothing, we just don’t know what it means.

If there were better organic gel test databases out there, I could match velocities and gun models.

I did that with ShootingTheBull (P938) and 5pins (LCP).

Couldn’t do it with Brass Fetcher but the amount of increased velocity (assuming he actually used a 5” barrel like he said), would be a LOT to get an extra 0.10 of expansion.

So could be his failure to report what gun barrel length he shot faithfully.

Maybe he actually shot a 4” barrel!

But then it makes my data even more accurate…

[JCN]

So @the Schwartz I think I was wrong.

I think the Brass Fetcher data is crappy.

I just looked at some YouTube videos of organic gel (but with denim) and this load and they’re seeing expansion of 0.89 which is more than my 0.82.

That would jive with that Schwartz is saying.

A little annoyed that Brass Fetcher data is so far off.

But goes to show even “professional” data can be wrong.

And it’s good that we are having a dialog of alternate explanations of the results are (in this case the control data is corrupted).

[the Schwartz]

Well, I used the same barrel length that Brass Fetcher did.

So the velocity should be similar.

''Should be'' is not the same as ''is''. That is an assumption, JCN.

And I don’t think my 5” barrel is going to give 200fps higher velocity than his.

We call the data point “a clue.”

It’s not proof, but should very much bring out the possibility that there’s more than density at play.

That's correct. It is not proof. Neither are ''possibilities''. ''Possibilities'' is just another word for ''guesses''. You mention ''possibilties'', but again, have you proof of any of those ''possibilties''?

Bernoulli's equation, proposed in Hydrodynamica written in 1738, has stood the test of time. I think that it rests on pretty solid ground 284 years later having never been disproved.

You want things to “mean less than nothing” but that’s your bias to ignore everything except what you’re wanting to believe.

I prefer documentable proof, which requires the proper management and analyses of data.

Couldn’t do it with Brass Fetcher but the amount of increased velocity (assuming he actually used a 5” barrel like he said), would be a LOT to get an extra 0.10 of expansion.

So could be his failure to report what gun barrel length he shot faithfully.

So, what are the odds that all of BrassFetcher's test data occurred with all of the test bullets hitting the test fixture at exactly factory-specified velocity?

Now that is what we call a clue!

Maybe he actually shot a 4” barrel!

Maybe?

Maybe not.

Another assumption.

But then it makes my data even more accurate…

Uh...no.

[the Schwartz]

So @the Schwartz I think I was wrong.

I think the Brass Fetcher data is crappy.

I just looked at some YouTube videos of organic gel (but with denim) and this load and they’re seeing expansion of 0.89 which is more than my 0.82.

That would jive with that Schwartz is saying.

A little annoyed that Brass Fetcher data is so far off.

But goes to show even “professional” data can be wrong.

And it’s good that we are having a dialog of alternate explanations of the results are (in this case the control data is corrupted).

OK, so here's a constructive idea if you're so inclined....


If you really, truly wish to establish some sort of correlation to the terminal ballistic behavior (expansion and depth of penetration) in both your new 15% iteration of the CBG product and properly prepared shear-validated 10% ordnance gelatin, why not go straight to the horse' mouth, JCN?

When you test the 15% iteration of the CBG product and 10% ordnance gelatin why not perform a direct test comparison between the two by firing the same number of rounds of the same ammunition into each material?

That way, you have data that is free of variability that might be introduced by using someone else's data (you've seen how that works with the tabular BrassFetcher stuff) and you could vary the fraction of the CBG 10% and 20% products to correlate to a known, proven, repeatable (BB penetration between 8.5 ± 0.4 cm at 591 ± 13fps) standard— 10% ordnance gelatin.

But now, here's where you get your mind blown, friend... (drum roll, please...)

Because Fackler states that there is no need to use anything more than BB calibration to verify/confirm the validity of the ordnance gelatin test block, there is no need to mess with the expense and hassle of mixing up all of that 10% ordnance gelatin into which you will need to fire a fortune's worth of JHPs to get your answer because all you really need to do is determine the correct titration of the two CBG products it takes to reproduce the BB penetration between 8.5 ± 0.4 cm at 591 ± 13fps that it takes to confirm the validity of the medium. There's your test design.

And, BBs are far, far, far cheaper than ammunition.


Science!

[JCN]

OK, so here's a constructive idea if you're so inclined....

If you really, truly wish to establish some sort of correlation to the terminal ballistic behavior (expansion and depth of penetration) in both your new 15% iteration of the CBG product and properly prepared shear-validated 10% ordnance gelatin, why not go straight to the horse' mouth, JCN?

When you test the 15% iteration of the CBG product and 10% ordnance gelatin why not perform a direct test comparison between the two by firing the same number of rounds of the same ammunition into each material?

That way, you have data that is free of variability that might be introduced by using someone else's data (you've seen how that works with the tabular BrassFetcher stuff) and you could vary the fraction of the CBG 10% and 20% products to correlate to a known, proven, repeatable (BB penetration between 8.5 ± 0.4 cm at 591 ± 13fps) standard— 10% ordnance gelatin.

But now, here's where you get your mind blown, friend... (drum roll, please...)

Because Fackler states that there is no need to use anything more than BB calibration to verify/confirm the validity of the ordnance gelatin test block, there is no need to mess with the expense and hassle of mixing up all of that 10% ordnance gelatin into which you will need to fire a fortune's worth of JHPs to get your answer because all you really need to do is determine the correct titration of the two CBG products it takes to reproduce the BB penetration between 8.5 ± 0.4 cm at 591 ± 13fps that it takes to confirm the validity of the medium. There's your test design.

And, BBs are far, far, far cheaper than ammunition.


Science!

The last part: not possible. I’m agreeing with you and the Haag data that because of construction differences you’ll NEVER get scalability of the BB titration to the final product (handgun penetration and expansion).

We all agree that the products are fundamentally different and more importantly behave differently at different velocities.

So the 590fps BB isn’t going to ever work.

And the CBG will never do what organic does.

Totally agree with that.

As to the first part, I’m more inclined to use a fackler box or pure water as the prelim testing if you think that’s a reasonable intermediate step.

[JCN]

And just to be clear, learning is the most important (and enjoyable) point of this for me as a hobby.

I find this fun and I appreciate @the Schwartz helping me work through some of this.

I might eventually wind up exactly where he’s coming from, or might come up with a modification of what might be useful for me instead (maybe it’s just pure water testing).

[JCN]

Do these sound reasonable:

https://john1911.com/making-a-fackler-box/



At my personal range I could see making something like this semi-permanent and just filling with a hose when needing to test something.

[the Schwartz]

Do these sound reasonable:

https://john1911.com/making-a-fackler-box/



At my personal range I could see making something like this semi-permanent and just filling with a hose when needing to test something.

It's as good a place to start as any that I can think of.

If average expansion is the same in both mediums (an 'n' of 5 in water and 5 in CBG for each design fired with maybe 25 different designs being used) may give you enough to get a working idea. Of course, the statistician in me is always looking for at least an 'n' of 1,000 but I realize that that simply isn't possible under the current set of circumstances.

The way that I obtain average expansion, if you have seen some of the work that I've done here is to take a picture of the expanded projectile next to a measurement standard (a steel ruler with 1/16th'' graduations) with both in the same focal plane, convert it to a PDF, then use the PDF's ''area measuring tool'' to trace the perimeter of the projectile in the picture and then solve for radius by working backwards from the computed area of the projectile. Please note, that the scale when you do this sort of thing is never one to one so you will need to determine how many inches the PDF says one scale inch in the image is actually equal to (using the PDF'slinear measuring tool), then divide your final computed radius by that value.

Your method, does not even require the use of any of the five mathematical bullet penetration equations unless you want to make that computation just to satisfy your curiosity.