GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Kinetic45^ on October 12, 2018, 11:02:49 PM
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I'm always testing, well, everything, since that' a big part of the fun of shooting airguns. I have air rifles in so many calibers but the ones I shoot now days are the .457, .357 and some .25s.
And not pellets much either, I shoot slugs of which there are some good 'store bought' but I grew up casting with my Dad and have continued all my life. I have almost 80 molds, most of which have not been used for years because their bullet did not preform in accuracy or possibly in terminal performance. Some of those bullet were tested in the field taking game but it's hard to make determinations WHY a bullet preformed or not because of so many variables there. One success does not prove anything the next time.
So if you are testing bullets you eventually come to shooting into some sort of consistent medium that will simulate life but can be used many times so you can establish a 'string' of data to analyze and make conclusions.
Of course, I always dug various bullet out of the backstop but the dirt is so hard everything expands so you can't really tell anything 'real'.
Living on the bayou the soft mud exposed when the tide is down is awesome to shoot... a 45-70 fired straight down off the pier will blow a bowl shaped hole 20" across and 10" deep and flying mud sprays out and covers everything in 18 or 20 feet. (and then you get to wash n detail all the boats because they are covered with mud and you are grounded for a week, haha)
I graduated to newspaper, then wet newspaper then bagged newspaper saturated in water which leaves an impressive permanent cavity but since I also hunted a lot and dressed my game I knew it was better but again the media was too hard and was giving too much expansion.
Since tissue is mostly water I built a big trough 24" x 24" by 72" open at one end (and the top) which I bolted visqueen plastic across the end to make a 'window' to shoot through. The theory was that a bullet would punch into the plastic with not much more resistance than skin (not thick hide now, understand) and start expanding in the water and would expend all it's energy and come to a stop and drop down to the bottom for recovery and examination/measurement. I built it big because some shots were going to be taken at up to 350 yards (I hunted with powder burners back then) and I wanted to HIT, even if the bullet was a little off from where I aimed (much snickering n haha from old friends... my ears are burning).
Now for you math minded people who immediately caught the fly in the ointment, the volume of the trough is: 175 gallons and each time I used it I had to dip 5 gallon buckets into the water and tote them to the trough so you don't do that casually! Only for bullets you were seriously testing! Not counting the replacement time for the plastic sheet across the end. It would stand up to a couple of shots but sometimes the hydrostatic force would blow it out and ALL THE WATER DRAINED OUT!!!! Then there was the problem that sometimes bullets veer off out of their flight line... having holes , long diagonal holes blown into the side of the trough wood were not conducive to shooting more that day either (eventually the trough was 'shot' and instead of rebuilding it one more time I just discarded it). And 72" / 6 feet sounds like any bullet would stop in that distance... but it was amazing how many holes I patched in the far end too!!! {.458 Win Mag with 500 gr cast RN will do it at anything under 50 yards. .375 H&H, .35 Whelen, 30-06 with WW1 surplus ball...}
But overall, it worked and I learned a lot about expansion at various velocities.
A little diversion in subject that has generated a lot of heated words and feuds and that is hydrostatic shock. It's not supposed to happen at our velocities BUT the fact is that a temporary wound channel usually opens up even at subsonic velocities (even a .177 pellet shot into gelatin and filmed produces a tiny ballooning and some permanent wound channel in the few inches it travels) and that 'pulse' does some damage and how big it balloons up to and how long it is inside the animal COUNTS! Real world experience in butchering has convinced me that even below the levels where hydrostatic shock happens a subsonic pistol or air rifle bullet does more than just punch a hole. And there are LOTS of videos on YouTube of gelatin shots (look at the right kind, guys, OK? Not the booze loaded ones, haha) where we see the temporary wound channel ballooning.
So for deer and hogs I just want to know what is happening in the first 12 to 16 inches because that's how thick most of them are.
Note I have hunted feral cattle and shooting a mad 2000 pound bull charging you, you want PENETRATION and are hoping the bullet goes so far it comes out his a**! But that's an exception.
But eventually I wanted more realistic testing and that leads to ballistic gelatin.
Again, as a kid raised by grandparents and parents who had 'Depression Mentality' you just did not think of going out and buying much store bought if you could DIY it.
So for years as I 'evolved' I started making my own ballistic gelatin and boy was THAT a learning curve and a lot of wasted Knox!
I still make it but mostly to backstop the store-bought (I can finally afford) to catch the slugs that go all the way through the 'good stuff' .
Which brings me to the ultimate reason for this post.
Commercial ballistic gelatin is EXPENSIVE and unless you are a city, county, state or federal government most people would/could seldom can afford it.
Only serious experimenters buy it and even I remelt and reuse it till its too yellow to see through but can still be cut open to see the permanent channel left..
But there is a limited time sale that I wanted to let my fellow GTA members know about and that is this:
Clear Ballistics is selling a batch of 'Less than perfect" 10% FBI block for HALF PRICE!
So instead of $130 it is only $70
Note the plastic wrap is still on the block pictured,when that is removed iot is crystal clear and you can see tiny bubbles in it which will not hurt OUR testing.
I also have NO IDEA why the data sheet is upside down as it is NOT in my files... I have deleted it and reloaded it and that still happens, gerrrr FIXED IT
https://www.clearballistics.com/shop/less-than-perfect-10-ballistic-gelatin-fbi-block-16x6x6/ (https://www.clearballistics.com/shop/less-than-perfect-10-ballistic-gelatin-fbi-block-16x6x6/)\
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That was some fun informative reading, a lifetime of experience in words.
Thanks for sharing that Carl.
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Good stuff from a fellow forced tight wad! ;D
Knife
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I think every gun owner has done some similar things.... I played around with home-made ballistics gel, but I found it VERY temperature sensitive.... You are supposed to use it right out of the refrigerator….
Best practices in managing the temperature of your ballistic gelatin blocks include:
↪ Do not remove the gelatin block from refrigeration until ready to shoot.
↪ Keep gelatin block in a shaded area — avoid direct sunlight.
↪ Ensure that gelatin block is at a homogenous temperature of 37.5–39.5°F prior to shooting.
Here is a very complete discussion about the effects of temperature on it....
http://www.brassfetcher.com/Gelatin%20Temperature%20Effect/Effect%20of%20Gelatin%20Block%20Temperature.html (http://www.brassfetcher.com/Gelatin%20Temperature%20Effect/Effect%20of%20Gelatin%20Block%20Temperature.html)
Rather than deal with all of that, I now use melt-and-pour soap, which is stable over a wide range of temperatures, and easily reusable.... In addition, the wound cavities don't close up like with ballistics gel, and are easily measured, photographed, and dissected, and the bullets can be recovered.... It is a lot firmer than 10% BG, but may be similar to the 20% BG mentioned in the above article, although I have never compared them.... I can tell you that a .22LR high velocity solid penetrates about a foot into it.... Here is what a block looks like after being impacted by couple of .257 HPs at 130 FPE....
(http://i378.photobucket.com/albums/oo221/rsterne/Ballistics/257calat130FPE_zpscc93e88c.jpg) (http://s378.photobucket.com/user/rsterne/media/Ballistics/257calat130FPE_zpscc93e88c.jpg.html)
The FN bullets on the left had already travelled through the same size block shown (9" long).... I got a pack of twelve 2 lb. bricks, and I still have several I have never melted.... because it is so easy to reuse.... I bought it here....
https://www.newdirectionsaromatics.ca/products/melt-pour-soap-bases/melt-and-pour-soap-base-clear.html (https://www.newdirectionsaromatics.ca/products/melt-pour-soap-bases/melt-and-pour-soap-base-clear.html)
Bob
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Yup, with DIY gel you transport it in an ice box. It's just part of the gear and becomes routine.
But the synthetic is so much more flexible in use and forgiving.
On the glycerin soap, I've used it but I worked it to a higher water content to make it softer because if it's dried out it is so hard it gives more expansion than 'real world' hunting. It can be a good comparison though if you shoot a known bullet into it and see how much more expansion then sort of 'subtract' that extra amount in your mind from the new bullet.
But the commercial ballistic gel results are almost identical to real world and no adjustment has to be made and that's just... easy/nice/accurate/advantageous.
All have their place at the shooting range.
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Shows what I (don't) know.... I had no idea that modern ballistics gel was synthetic and did not require refrigeration….
Bob
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yea i have the same less than perfect. only thing i noticed that it had a few black specs great deal. also showed me what does and doesnt actually expand.
for instance:
bbts expand beautifully in .22 but very little in .25
most every pellet expands better in .25 the crow magnums sound like a belly flop when hitting a iguana!
the .22 crow magnums dont expand much :(
only .22 i tested that expands awesome is the crossman destroyers.
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Shows what I (don't) know.... I had no idea that modern ballistics gel was synthetic and did not require refrigeration.
Same here.
Nice post Carl, thanks for the tip on the deal, just bought some myself.
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I just thought I would mention that I have remelted my block four times and if you carefully control the temperature it only shows a tinge of yellow. The biggest problem is loss of material when you are removing bullet fragments.
I actually bought two blocks and am using the 'spare' to make up that loss.
In four remeltings I've only used about an 1-1/4 inch off the end.
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Hi carl, post some pictures of your results. I'm loving this thread.
This is awesome stuff.
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Hi carl, post some pictures of your results. I'm loving this thread.
This is awesome stuff.
Sorry bout that.
I know nowadays if there's no pic 'it didn't happen' but I did not take pictures for years, just kept one unfired sample bullet and one good example of the fired. A 50 year collection.
There's a story there: A couple of years ago in a divorce she-devil disposed of my collection before she moved out while I was out of country on a job.
FYI - Met her elk hunting in Oregon, she was a hunter/target shooter/reloader too and had/has more guns than I do, haha. I used to work as a gunsmith too and she asked for a take-down, engraved Savage 99 in .308 as a wedding dowry from me. I worked on the road all the time for GE and she found someone else 20 years older at her work she like better.
Mostly I keep it all in my memory of what did what.
The last couple of years I started taking some videos of the temporary cavity but stupidly only had it all on one drive with no external hard drive nor cloud backup... my dumb is an example to you to backup because this August I had a hard drive crash and it was not recoverable even though I sent it off for one of the big outfits to try. Still been shooting the gel but not bothering to set up the camera and 12V backlights and all that. Just look at the permanent cavity and the expanded bullet and that's been good enough for me. I'll start taking pictures from now on again for GTA.
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https://www.youtube.com/watch?v=YaoZrcI0glA&t=3s (https://www.youtube.com/watch?v=YaoZrcI0glA&t=3s)
I like using clay! or Ballistic gel made at home ;D
Thats a great deal, I wish I had the cash to pick up a block