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-   -   Homemade ballistic gel (http://glocktalk.com/forums/showthread.php?t=1445824)

Andrew Wiggin 10-02-2012 10:38

10mm gelatin tests
 
Go to the end of the thread for the most recent test.


So my lovely and thoughtful wife bought me a 10mm Witness for Christmas and I've had a lot of fun working up loads for it. Problem is there really isn't a whole lot of terminal ballistic data available so I have no idea which bullets will hold together well or penetrate to what depth. I did a couple water tests but those were less than definitive and disappointing if the penetration results were to be believed. Worse, it seemed that they were inconsistent with other available data. So I decided the only way to get good data was to gather it myself. Here is my attempt at ballistic gel. Let me know how badly you think I did.

Proper ballistic gelatin is 10% by weight 250 bloom photographer's gelatin. That means 10% of the weight is gelatin and 90% of the weight is water. It is kept at 39 F and is calibrated by a .177 cal steel BB at 590 fps +/- 15fps. The calibration shot(s) should be between 2.95"-3.74". 250 bloom photographer's gelatin is expensive so I bought grocery store unflavored gelatin. I did the math and found that 10% should put me at about 1 cup of water per ounce of gelatin. I bought three 8oz packages of Kroger gelatin and mixed it up with 24 cups of water but it didn't calibrate correctly. I bought another three 8oz packages, Knox this time and mixed it with 18 cups of water, melted both batches down and mixed together. So that's a total of 48oz (by weight) of gelatin with 42 fl oz of water.That got me close to what I was looking for but I had to melt and add water a couple times again. The final mix was 48 oz gelatin to 45 cups water. I've since doubled the batch and confirmed that ratio, but if you make some up, it might be better for you to start a cup or two short just because it's easier to add water than remove it. My procedure follows.

Open all the packages into a bowl for easy pouring. Measure 45 (or a bit less) cups of hot tap water (I have since found that cold water produces less clumping so I mix it cold and then heat in a double boiler) into a bucket, along with a few drops of bleach (to prevent mold) and a few drops of Jet Dry to prevent foaming. Start the water moving with a mixer and slowly pour in the gelatin. Be careful to pour slowly enough to avoid clumps but some are probably inevitable. Allow to cool and refrigerate for about a day. Heat in a double boiler until just melted, stir, and pour into molds. Allow to cool and refrigerate again for several days. It gets firmer after several days and it has to be all the way down to 39 throughout for calibration to have any meaning. Fire a 590 fps +/- 15 fps .177 cal BB into the block and measure the penetration. In the picture below, the bottom shot took place at about one day in the fridge and it measured 4". The shots above that took place at about three days and measure, bottom to top: 3", 3 1/8", 3 1/4", 3 1/8". The other picture was a .22 cal pellet from a Benjamin Sheridan pellet rifle just for fun. It penetrated 4 1/2".

After a test, I cut the blocks to get good photos of the "wound" track and put them in a double boiler to remelt. I just use a plastic bucket (about 2 gal, I think) for the gelatin and a large stock pot for the water. I keep the stove on medium and try not to let the gelatin completely melt while it's in the water. As it melts, I pour it out and add more blocks to keep the temperature from getting too high. When I'm down to the last of it, I remove it from the heat before it's completely melted and let it finish melting on the counter. The warm gelatin is usually enough to melt a few smaller chunks. I pour through a wire mesh grease splatter screen first to remove the larger chunks of denim, dirt, lead, copper, and BBs, then I pour through a "permanent" wire mesh coffee filter to remove the smaller particles. It all goes into a large bucket until it's all melted and then into the molds. For molds I just use cheap Sterlite tubs from Walmart.

http://imageshack.us/a/img845/7182/dsc03720me.jpg

http://imageshack.us/a/img546/3208/dsc03721a.jpg




Here's a new test with a bit more precise data:

BB calibration: 590.8 fps, 3" penetration
.22lr from Walther P-22: 36 gr CCI Mini-Mag hollow point at 970.0 fps, 8 3/8" penetration
I got distracted by something shiny and forgot to place 4 layers of denim in front of the .22lr shot.


http://img547.imageshack.us/img547/5...ciminimag9.jpg

Andrew Wiggin 10-02-2012 10:39

I went ahead and melted the blocks down to mix in a cup of water. I think I might actually need two cups but you can always add more water. It's a lot harder to get the water out. I poured the gel through a screen and took a pic and measurements of the .22lr. The retained weight was 35.7 gr and the diameter was approximately 0.335". I didn't find any fragments. There was absolutely no deformation on the pellet.


http://img825.imageshack.us/img825/5...g0335india.jpg

Any Cal. 10-02-2012 12:33

Wow! Maybe you need to find a hobby or smething... :-)

Nice approach, I am interested to see how it plays out.

nickE10mm 10-02-2012 15:13

Very cool ... :popcorn:

Taterhead 10-02-2012 20:31

Cool project! I barely have enough time these days to keep up with loading and ballistically unloading my brass.

I look forward to your results. Thanks for starting a cool thread.

Yondering 10-02-2012 22:59

I like it. Sure, it's a lot of work, but this sounds a lot easier (and cheaper) than true ballistic gelatin.

Couple questions:
- What are you using for molds?
- Why do you have to let the gelatin set up for a day, and then pour it into the molds, instead of putting it straight in the molds? Is this for consistency?

The BB pictures are cool; it looks like the BB's actually bounced back a tiny bit.

I wonder if you could inject food dye in the bullet track for better pictures?

I'm going to have to try some of this. Thanks for posting.

Andrew Wiggin 10-04-2012 10:31

It's definitely cheaper but my process is pretty close to what I've read on preparing the real stuff.

Just using el cheapo Sterlite tubs I found at Home Depot. They are 6 qt, 13 5/8" x 8 1/4" x 4 7/8". (Now I'm using twice as much in larger tubs) Two of them fit my batch of gelatin (48oz dry) perfectly. I wiped the inside of the tubs with some vegetable oil and a paper towel so the gelatin would release easily (I discovered this isn't necessary, either).

When you first mix the gelatin, it's not really thoroughly mixed and there are small clumps and inconsistencies because the gelatin isn't fully hydrated. It takes some time for the water to completely soak in. It might work to go straight into the double boiler but the procedures I've read for real 10% ordnance gel have it sit for several hours in the fridge.

I do think the BBs either bounced back, as you say, or split the gelatin farther forward than they actually traveled. Nevertheless, I'm measuring from the leading edge of the BB.

The track would probably be more visible but then the dye would stay in when I remelted and the gel would gradually darken.


Recalibrated today and I'm dead on 3" again with a BB velocity of 595.9 fps. I'm going to remelt and add two cups of water. I'm going to shoot this SOB on Saturday, regardless of how it calibrates. I have more opportunities to fiddle with the mix than I do to get out and shoot. I think I'll hit it with a 165 gr Gold Dot at 1,302 fps first.

nickE10mm 10-04-2012 10:39

Quote:

Originally Posted by Andrew Wiggin (Post 19484674)
It's definitely cheaper but my process is pretty close to what I've read on preparing the real stuff.

Just using el cheapo Sterlite tubs I found at Home Depot. They are 6 qt, 13 5/8" x 8 1/4" x 4 7/8". Two of them fit my batch of gelatin (48oz dry) perfectly. I wiped the inside of the tubs with some vegetable oil and a paper towel so the gelatin would release easily.

When you first mix the gelatin, it's not really thoroughly mixed and there are small clumps and inconsistencies because the gelatin isn't fully hydrated. It takes some time for the water to completely soak in. It might work to go straight into the double boiler but the procedures I've read for real 10% ordnance gel have it sit for several hours in the fridge.

I do think the BBs either bounced back, as you say, or split the gelatin farther forward than they actually traveled. Nevertheless, I'm measuring from the leading edge of the BB.

The track would probably be more visible but then the dye would stay in when I remelted and the gel would gradually darken.


Recalibrated today and I'm dead on 3" again with a BB velocity of 595.9 fps. I'm going to remelt and add two cups of water. I'm going to shoot this SOB on Saturday, regardless of how it calibrates. I have more opportunities to fiddle with the mix than I do to get out and shoot. I think I'll hit it with a 165 gr Gold Dot at 1,302 fps first.

:-) me likey

Yondering 10-04-2012 22:27

Very cool, and thanks for the answers. Putting this on my list of projects to do...

I'd like to see your results when you shoot it.

Taterhead 10-04-2012 23:09

Quote:

Originally Posted by Andrew Wiggin (Post 19484674)
I think I'll hit it with a 165 gr Gold Dot at 1,302 fps first.

That should be a winner. Hopefully you'll get some good photos.

Andrew Wiggin 10-05-2012 14:30

Quote:

Originally Posted by Yondering (Post 19486796)
Very cool, and thanks for the answers. Putting this on my list of projects to do...

I'd like to see your results when you shoot it.

Definitely. I'll shoot it tomorrow and probably post results on Monday(ish).

If the test is successful and I'm happy with the performance of the gelatin, I'll post a more straightforward rundown on my process.

Andrew Wiggin 10-08-2012 13:46

I had some trouble with my chrono and it missed the velocity on several BB calibration shots. There were also a few that came in well under the acceptable velocity of 590-610fps. My BB gun seems to shoot faster when it's cold. Maybe I'll keep it in the cooler with the gel next time. http://www.ar15.com/images/smilies/smiley_abused.gif I finally got a couple shots that were close to the right velocity so the calibration shot will be 586.4 fps (still a touch low) and 3.5". The 10mm shots are taken through 4 layers of denim using an EAA Witness 4.5" barrel.

First up is 180 gr XTP over 11.8gr of AA#7, 1.255" COL, at a measured impact velocity of 1,290. Penetration is 13.25". It exited the first block and went a about an inch and a quarter into the second block. Next time I'll have to cut the blocks even so there is no air space between them. I don't know how much, if any, effect that has. You can see that this bullet fragmented a bit. I was going to weigh the recovered fragments, but the piece you see in the on picture got left out there. Sorry. Maximum expansion is 0.898" and minimum is 0.636". Retained weight is 174.8 gr.


http://imageshack.us/a/img824/3228/dsc03750o.jpg

http://imageshack.us/a/img844/3691/dsc03776j.jpg

http://imageshack.us/a/img18/1840/dsc03779dn.jpg

http://imageshack.us/a/img18/9585/dsc03788ti.jpg

Andrew Wiggin 10-08-2012 13:46

Deleted to speed page loading.

nickE10mm 10-08-2012 13:49

I asked too soon ... removed post.

Andrew Wiggin 10-08-2012 13:49

Since the XTP barely touched the second block, I reversed it and placed it at the front. Next up is 165 gr Gold Dot over 12.3 gr of AA#7, 1.255". I missed the actual impact velocity of this shot but the average for this load is 1,310 fps. Penetration was 12". This shot exited the first block and was found laying between the two. There was absolutely no fragmentation or jacket separation. These Gold Dots are TOUGH. Maximum expansion was 0.837" and minimum was 0.779". Retained weight was 165.0gr.



http://imageshack.us/a/img832/1963/dsc03752fa.jpg

http://imageshack.us/a/img267/2628/dsc03757h.jpg

http://imageshack.us/a/img11/121/dsc03782et.jpg

http://imageshack.us/a/img802/2567/dsc03783p.jpg

http://imageshack.us/a/img341/4002/dsc03785s.jpg

Andrew Wiggin 10-08-2012 13:49

Deleted to speed page loading.

Taterhead 10-08-2012 20:39

Nice work, Andrew. I really like those 165 gr Gold Dots. That seems to be a really good speed for them.

Quick side note, you probably mean 1.255" COL rather than 2.255" in posts 12 & 15.

Andrew Wiggin 10-08-2012 20:49

Quote:

Originally Posted by Taterhead (Post 19498883)
Nice work, Andrew. I really like those 165 gr Gold Dots. That seems to be a really good speed for them.

Quick side note, you probably mean 1.255" COL rather than 2.255" in posts 12 & 15.

LOL, sorry. I'll fix it.

Yondering 10-09-2012 00:10

Cool stuff, thanks for posting your results.

Re. the space between the blocks, how about flipping one block upside down? That should let the ends mate up if they're both from the same mold.

Andrew Wiggin 10-09-2012 09:33

I feel kinda dumb now. Good call.

Andrew Wiggin 10-11-2012 10:00

I'm going to shoot this stuff again Saturday, if we can get a sitter. I've had some comments on the other board that grocery store gelatin doesn't yield the same results so I plan to fire at least one shot of .40 S&W 180 gr factory Gold Dot into it from my Glock 22 to help establish a baseline that we can compare to professional tests. On the one hand I'd like to get on with testing lots of other loads but on the other hand I think I need to address the concern that my gel may not yield accurate results. To that end I was thinking that I could probably get two shots into each block, for a total of 4 shots. So what do you think? Should I shoot the block four times with .40 or is one shot sufficient to tell us whether the gelatin is close? If I only shoot it once with the .40, what other load do you want to see tested? The two I'm most interested in seeing are Buffalo Bore 10mm 180 gr JHP and my hand loaded 65 gr Game King over 24.0 gr of TAC at about 2,950.

nickE10mm 10-11-2012 11:11

I'd like to see the 135gr Nosler at 1500+fps... and I'd like to see a 200gr WFNGC at 1300+. :) The 180gr GD is also something I'm interested in.

RWBlue 10-11-2012 11:50

Sorry for jumping in late, but you might also want to look at Corbin gel.
http://www.corbins.com/sim-test.htm

I bought some.
Used it.
Loved it.
Remelted it multiple times.
Stored it in ziplock containers.

Andrew Wiggin 10-12-2012 18:16

Quote:

Originally Posted by RWBlue (Post 19507272)
Sorry for jumping in late, but you might also want to look at Corbin gel.
http://www.corbins.com/sim-test.htm

I bought some.
Used it.
Loved it.
Remelted it multiple times.
Stored it in ziplock containers.

tnoutdoors9 is already doing 10mm tests on YouTube using that stuff. I believe it is probably pretty close to ballistic gelatin but some folks have been critical of the fact that it is NOT actually gelatin and therefore may yield dramatically different results.

Besides, this batch cost me $40. SimTest is a lot more expensive.

RWBlue 10-12-2012 20:07

Quote:

Originally Posted by Andrew Wiggin (Post 19512421)
SimTest is a lot more expensive.

Simtest is reusable. Again and Again and Again and .... Just set it up on a clean surface. The jacket and lead will fall to the bottom when remelting.

BTW, If you like what you are doing, continue. If you don't..... I just wanted to post another option.


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