Non-scientific hobbyist entertainment with synthetic gel.

[JCN]

This reminds me that I really would not want to be shot with a 45 ACP…

[JCN]

The 45ACP expanded more and penetrated less than what they got in organic gel. That’s part of the lack of fidelity of the synthetic gel.

So that at least supports that even though less dense than water, can still get more expansion (and less penetration).

That it doesn’t match with organic across different sizes and velocities is a valid criticism of the synthetic.

I can tell the bullets look a little different than the pictures of bullets in the organic.

So there obviously is a difference in how it interacts with the medium.

I’m pretty satisfied with ~15% gel as a decent handgun cartridge testing medium for a hobbyist.

[DMCutter]

@JCN, I was just getting ready to ask about expansion. I know expansion has sensitivity WRT velocity and I was wondering how sensitive it is WRT density of the target medium. Those diameters look very consistent with most all the videos I've seen of ballistic testing, so I guess the delta in density doesn't make a significant difference in expansion in this range of velocities. I reckon that's kind of moot since most of the things we would tend to shoot would be as dense or denser than organic gel. But it's interesting and seems to validate that HST is good shit.

[JCN]

@JCN, I was just getting ready to ask about expansion. I know expansion has sensitivity WRT velocity and I was wondering how sensitive it is WRT density of the target medium. Those diameters look very consistent with most all the videos I've seen of ballistic testing, so I guess the delta in density doesn't make a significant difference in expansion in this range of velocities. I reckon that's kind of moot since most of the things we would tend to shoot would be as dense or denser than organic gel. But it's interesting and seems to validate that HST is good shit.

So for example, in my first mixing attempt I got 15” penetration and 0.62” expansion.

My thicker prep, I got 13” penetration and 0.66” expansion.

If I look critically at the bullet faces, the ones shot at organic gel have the petals spread further suggesting that the initial impact was more abrupt (which would be consistent with the higher density of organic over even the thicker synthetic). But the synthetic polymers can be pretty draggy which explains how you can get less penetration than organic even at lower densities (when the right mix of polymers are used).

But IMO good enough even if it’s not perfect.

I love the convenience of being able to take a few shots and then come back a different day and take a few more on the same block.

I still haven’t spent any more money than just ammo for what I’ve had lying around.

(Edit: clarification on the numbers above were for 9mm HST+P shot out of a 3” barrel…. The 45 ACP had more expansion than organic gel, and not surprisingly less penetration).

[RevolverRob]

This thread makes me think about a stupid mad scientist idea.

Sometimes I do tissue cell cultures in agarose gels. Maybe I should just grow masses of tissues in agar long enough to get a big block to shoot it. It wouldn't be a tissue stand in, it would be tissue.

That sounds disgusting overall and would no doubt violate every BioSafetyLevel for a lab. And also probably isn't kosher with funding agencies.

Still...you can make agar gels at home and you could use tissues harvested from your pet axolotl...

[JCN]

This thread makes me think about a stupid mad scientist idea.

Sometimes I do tissue cell cultures in agarose gels. Maybe I should just grow masses of tissues in agar long enough to get a big block to shoot it. It wouldn't be a tissue stand in, it would be tissue.

That sounds disgusting overall and would no doubt violate every BioSafetyLevel for a lab. And also probably isn't kosher with funding agencies.

Still...you can make agar gels at home and you could use tissues harvested from your pet axolotl...

As a semi-serious response, the density of the agarose would be the thing that determines the results because the cells you’re growing don’t have rigid structure (no extra cellular matrix) and you couldn’t make a block large enough without them all dying from lack of oxygenation.

So if you’re going to make an agarose block that big, you might as well use organic gelatin…

[JCN]

On @Clusterfrack recommendation and since I’m starting to play with my G20 more…

I bought the Federal 10mm 200gr HST that @5pins tested in organic and will test in my ~15% synthetic gel.

Of note, when he tested it went through the 16” gel block so there’s not specific distance data but it’s “good enough” because it went far enough without going into the backing block when he tested.

[Crazy Dane]

JCN, I appreciate the work you are putting into the clear gel. I grew up with all the gun rag experts using stacks of wet phonebooks or newspapers, " this new wunderbullet made it to page 83 in the fourth book" did not equate well when the books I was using only had 56 pages per copy. I hope that continued efforts by you and others will produce a medium that can be accepted or at least not poopooed on by the purist.

[JCN]

JCN, I appreciate the work you are putting into the clear gel. I grew up with all the gun rag experts using stacks of wet phonebooks or newspapers, " this new wunderbullet made it to page 83 in the fourth book" did not equate well when the books I was using only had 56 pages per copy. I hope that continued efforts by you and others will produce a medium that can be accepted or at least not poopooed on by the purist.

Thanks man, I think for the military / law enforcement / ammunition manufacturer that there is no reason to deviate from the pure FBI protocol in the full form. They have the resources to be able to do this with dedicated facilities and personnel and the database and expertise that has been accrued is only valid in the medium tested.

But for the hobbyist that might just be curious if their pocket pistol can generate enough velocity to expand a projectile (for example HST works, but Gold Dot doesn’t faithfully in short barrels) or to test random new loads and cartridges (like the Xtreme Defender) or to test penetration from atypical, non-duty guns (like a 1” barrel Taurus View), the clear gel has distinct advantages in convenience.

I mainly set out to debunk some of the erroneous conclusions that some purists misattribute to all synthetic gel rather than the too thin 10% clear ballistic preparation commercially sold.

Myth: synthetic gel overpenetrates and underexpands compared to 10% organic gel and always will because of reduced density.

JCN: False. Despite reduced density, the chemical properties of ~15% synthetic gel allow more expansion and less penetration than 10% organic gel when testing 230gr 45ACP out of 5” barrel.







Myth: If you made a gel preparation that worked with one bullet / load, you’d have to make separate formulations for each load you wanted to test.

JCN: False. When testing other handgun cartridges, 380 ACP, 9mm and 45 ACP all performed reasonably faithfully to their organic gel counterparts in the same ~15% synthetic gel.



Truth to criticism: synthetic likely won’t be faithful to organic across a large range of velocities because of the way the medium works differently ar different velocities compared to organic. But across an 850-1100 fps spread it looks like it’s holding up so far.

Will test with slower and faster to see where things fall apart but will need organic gel testing to corroborate.

[JCN]

Forgot the other one:

Myth: Synthetic gel is less consistent shot to shot

JCN: Synthetic gel is extremely consistent from shot to shot but has more sensitivity to compromised borders so follow up shots have to be spaced appropriately widely apart.