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Author: Subject: Home produced smokeless propellants
inspector071
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[*] posted on 8-3-2012 at 16:57
Home produced smokeless propellants


I'm curious to know if anyone has ever made their own smokeless propellents, either single base (nitrocellulose) or double base (nitrocellulose and nitroglycerine) and attempted to use them in a firearm. I know people mix up their own black powder for cannons and muzzleloading firearms, but smokeless propellants are a whole different animal, especially considering that some of the starting compounds are shock sensitive, powerful explosives. Black powder is comparatively hard to mess up.

I attempted to make my own Cordite a few days ago. As many of you may know, Cordite was a British double base smokeless propellant used extensively in rifle cartridges (namely the .303 British) and larger artillery shells. Cordite is comprised of roughly 58 parts nitroglycerine, 37 parts nitrocellulose and 5 parts petroleum jelly by mass. Acetone was used as a solvent and the mix was extruded into spaghetti like pieces, called cord powder, which led to the name of Cordite. Cordite was based off of Alfred Nobel's earlier development of Ballistite, which used camphor as a plasticizer/stabilizer. I believe this is Nobel's original patent for the stuff. I haven't been able to track down Cordite's patent yet, just the original ratios of NC, NG, and PJ.

Anyways, I weighed out the appropriate masses of nitrocellulose, nitroglycerine, and petroleum jelly. The mass totaled to just about 4 grams. The compounds were added into a small test tube. I added some toluene to thin the NG throughout the whole mix (toluene does not dissolve nearly fully nitrated guncotton). I then poured the mix into a small dish and added a few drops of acetone to dissolve the nitrocellulose and gel everything together. It was mixed thoroughly, then set to dry. As it started to harden, I tried to granulate it as much as possible with a small blade. After everything had dried, I had a small batch of about 1mm granules of Cordite. Not really cord powder, but the ratios and small grain size is all that mattered to me. I tested a few grains. It burned steadily and evenly, leaving behind a small bit of ash, but produced no smoke. I shoot firearms as a hobby, and reload my own ammunition so I have quite a stock of various powders. Some of them are double base, but I also have some triple base powders which add nitroguanidine as a flash supressor. I took a sample of commercial double base powder of the same mass and compared it to my Cordite. The burn rate was similar, even though the grains of the commercial stuff were a tad smaller and more even. The commercial powder also left behind a similar amount of black ash. Here is a video of that test.

The significant qualms I have about attempting to test homemade smokeless propellants is the quality and purity of the nitrocellulose and nitroglycerine (in particular the complete neutralization of the compounds to prevent self catalyzing decomposition) and the grain size of the final propellant. I certainly will NOT be loading my homemade Cordite into any of my ammunition, but I would be curious if homemade propellants could be tested by someone with appropriate gear, namely a way to get even grains or cords of powder and a heavy test barrel/gun. Obviously the "start small" rule of thumb would be much recommended. I'm sure loading data for the original charge of a Cordite filled shell such as the .303 British could be procured.
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killswitch
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[*] posted on 8-3-2012 at 17:08


Is the panic-buying in the face of Obama's possible reelection so severe you're having to make your own powders now?

/just kidding.

[Edited on 9-3-2012 by killswitch]
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killswitch
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[*] posted on 8-3-2012 at 17:11


The bigger problem for the home firearms enthusiast would be the primer. Lead azide is much more dangerous to handle than nitrocellulose.
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inspector071
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[*] posted on 8-3-2012 at 17:39


The primers that I use are lead styphnate, which isn't as scary as the azides. Any primers that are marked as lead free are almost always DDNP. Making the primaries seems easier than trying to fashion the shell of a primer, though. I guess that small cap of metal could be swaged in a press. I'm much more interested in testing the quality and reliability of a homemade smokeless propellent, however.
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[*] posted on 9-3-2012 at 08:29


Where exactly is this thread going?

Bring a smokeless propellant to the general public takes several years of research by professionals with decades of experience. Manufacturing a smokeless propellant by a Graduate-level student would likely involve several hundreds of thousands of dollars of testing equipment. Even at that point, it's a damn poor idea.

Using black powder / ammnio pulver as a substitute and devising a consistent "flame route" primer might be possible for an individual with a great deal of patience - however, those primers need to be micro-gram consistent. And although I agree with Killswitch here, I don't see this thread coinciding with Forum Rules. It is also edging close to the "practical-use issue".
Therefore if someone wants to interject some science here; fine. If not, let's leave home-made Smokeless Powder to people who have been working with burn ratios and initiation / burst-strength elements for decades.


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If you hand-load for a hobby, that is miles away from the energetic chemistry needed to mfg a propellant. Listed would be the chemistry agenda of each element, their experimental issues of time, means, math, initiation structure, propulsion modeling (& it's agenda). It is no small thing to tame a high explosive to become a propellant. It takes an enormous amount of study and research that is documented on a continuum so as to find pathways to burning formats rather than detonation formats.
If you have been hand-loading for any time now you know that TOO LITTLE powder can result in a catastrophic explosion of a firearm just as too much or a blunder of burning patterns. The deflagration issues mapped in a mathematical model of cresting pressure vs. resistance of the projectile needs to be outlined PRIOR to the development of the propellant itself. This is no small task. The polymers in Smokeless Powder are burning rate modifiers. Understanding how burning rate modifiers function in a High Explosive brought to a propellant has been under study for the entire history of smokeless powder.

The level of genuine science involved in energetic materials is voluminous. The overwhelming majority of people involved in this area of interest would love to see it risen an order of magnitude, rather than maintained at an entry level. We have several people here who have not posted in quite some time and frankly, I would like to see that change.

We DO have some Forum members with a science background in depth enough to map out some of these details but they are not simplistic by any means. That is why some successful powders have remained on the market for decades in both canister and bulk sales. Military demands for TBSP have even more complexities which would take several pages to even introduce.

This is a very interesting subject. I would love to see some modeling and details.




[Edited on 9-3-2012 by quicksilver]




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niertap
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[*] posted on 9-3-2012 at 15:18


You might consider side stepping the primer issue by adding a small amount of #0000 steel wool to the propellant and just using a 9v battery or a couple AA batteries. I always make my E-matches that way. Whistle mix being the pyrotechnic in the E-match.

Black powder isn't terribly high pressure, but I would still have the projectile fit quite loosely. I would never feel confident enough to shoot a snugly fitting bullet out of a home-made gun, without concrete in-between.


Slightly off topic, but the chamber pressure of different things like benzolift, smokeless, black powder, & whistle mix might be interesting. Haha I suppose flash powder could even be used, so long as the barrel is sub-millimeter.




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Ral123
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[*] posted on 10-3-2012 at 01:38


What's the problem with flash powder? Why sub-millimeter? And why depend on projectile fited quite loosely. Stuck it tight and use less propellant, that way there wont be surprises.
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killswitch
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[*] posted on 12-3-2012 at 18:18


Another possible consideration would be the addition of polynitrostyrene in place of some or all of the petroleum jelly.

The problem with nitrocellulose, though, is the complexity of the molecule. Not all of them will contain the same quantity of monomers.

If you want to attempt something really groundbreaking, try a mixture of PETN and Tetramethylene-tetranitrosamine, with an energetic binder such as polynitrostyrene. Such a mixture would have a very long shelf life yet be extremely powerful.

Slightly off-topic, but I heard that CL-20, when used as a missile propellant, leaves behind virtually no vapor-trail. Since the molecule has hydrogen in it, wouldn't the production of steam be inevitable?

[Edited on 13-3-2012 by killswitch]
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[*] posted on 22-10-2016 at 22:09


You could also try homemade. nitrocellulose stabilized with homemade diethel ether which converts the stabilized nitrocellulose into Poudre b used by the French in there early rifles in the later part of the 19th century or ammonpulver invented by Hiram maxim in 1888 and was used by german and Austria forces during the first world war do to a lack of smokeless powder in that time or a double based powder made from both ammonium nitrate and stabilized nitrocellulose combined 60/40 40 being the a/n and 60 being the n/c
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macckone
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[*] posted on 23-10-2016 at 08:15


Primary issues with home manufacture of propellants is chemical purity and cellulose nitration percentage. The second is grain size. Grain size has a dramatic impact on burn rate and pressure developed. More so than the nitroglycerin and nitrocellulose ratios. Varying the grain size follows a square law. Reducing the grain size by half quadruples the burning surface. Did i mention how important grain size is?
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[*] posted on 27-10-2016 at 18:26


There is a pretty substantial thread on home made smokeless powder, with some testing in firearms done and plenty of photos, courtesy of member Henig Brandt.

Starts to get interesting at around page 5...

http://www.sciencemadness.org/talk/viewthread.php?tid=22649&...

I do wonder if he ever cast .30 cal. Lead alloy bullets and re loaded 30-06 rounds with home brew shotgun/fast pistol flake powder equivalent materials he was making small batches of a couple years back?

The .22LR and .410 shotgun rounds described were at least functional with the home made materials. The 30-06 rounds made with jacketed bullets and 40% NG flake powder worried me a bit to hear of, although apparently no gun was destroyed/shooter injured.




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Jimbo Jones
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[*] posted on 28-10-2016 at 02:04


Quote: Originally posted by Bobmaccian  
.....a double based powder made from both ammonium nitrate and stabilized nitrocellulose combined 60/40 40 being the a/n and 60 being the n/c


That sounds really interesting.
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Hennig Brand
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[*] posted on 21-7-2017 at 11:40


Just noticed this,

Well thanks for the fair evaluation and compliments Bert. It is a fairly complicated subject and there are great dangers involved especially for the inexperienced. Like many dangerous things, such as driving a car, they can be done "relatively" safely with a working brain and some experience/knowledge to go on. Maybe part luck, but reasonable judgement most likely has kept me out of trouble all these years, not luck a million times in a row. No people, guns, or equipment were hurt in the making of those posts. ;) It was a bit risky, but some what controlled. Admittedly I took a few chances.

I didn't carry it all the way through, but far enough that I was, and am confident, that servicable propellants could be relatively easily and safely made by a competent amateur (and it wouldn't cost millions or take decades).

I have been working in a different province. I haven't fired a rifle or detonated anything in well over a year. "Detonation Deficit Disorder" has set in hard! Lol

I still have the equipment tucked away safely for another time.



[Edited on 22-7-2017 by Hennig Brand]




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[*] posted on 26-7-2017 at 14:02


The military has a sneaky trick they design bullets that destroy the gun and sometimes the shooter and conveniently leave them behind to be found by the enemy.

https://en.wikipedia.org/wiki/Exploding_ammunition
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[*] posted on 26-7-2017 at 14:05




https://atwar.blogs.nytimes.com/2012/11/07/dirty-tricks-of-g...
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[*] posted on 26-7-2017 at 14:58


This whole idea of too energetic of a propellant got me thinking of the space gun.

A space gun has never been successfully used to launch an object into orbit or out of Earth's gravitational pull.

Seems to me they could maybe use explosives on the outside of the barrel as well as a way to push in on it as way to prevent it from bursting.
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