Mixing powders

[pinne65]

I'm curious what would happen if you mixed fast and slow burning powders. The idea would be to prevent an early pressure spike and teetering coming from using only fast powder, and to prevent too much slow burning powder burning after it leaves the barrel. And ultimately be able to achieve higher velocities at lower maximum pressures.
Does this make sense, has anyone tried this?

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[badclam]

KABOOM!!! have your next of kin post the results.

 

[Trailboss]

This has been extensively studied over the years by many people, going back to Dupont and Hercules powder companies and many more. The British tried doing this with soft powder next to the primer and a hard chunk closer to the bullet. Some tried a leather washer in between different powders, some poured on on top of the other in a compressed fit. Most of these experiments turned bad and the results were very unstable. Your various powders are already blended while they are manufactured. They do their job quite well. It is so unlikely that you can improve on their formula that you have a better chance of discovering that Elvis is not dead and in fact, he lives next door to you.

 

[Mark W.]

The only place I have ever heard of this idea not ending poorly is in cap and ball revolvers. Where 4-5 grains of ffffg Black powder is put in the bottom of the cylinder while the rest of the 25-30 grains is fffg Black powder. This is supposed to give a little faster ignition to help with holding the pistol on target.

 

[deadshot2]

For a little mental exercise, think about how even the "mix" would be. Ever mixed peanuts and cashews? Peanuts and pretzels? For some darn reason, unless it's a substance dissolved in a liquid, they always separate or stratify. The small pieces to the bottom (quick burning) and the large pieces (slow burning) to the top.

The "Idea" is perhaps OK, there's just no way to do it and maintain a fully dispersed mixture.

The Powder manufacturers have had all their success from essentially layering EACH granule of powder. various methods of forming the granules, as well as their composition, gives you the best of all worlds or at least the best possible.

There is a practice known as "Duplex Loading". Some will use a "kicker charge" of a fast burning powder like Bullseye under the "main charge". This practice can be found among those with old black powder cartridges with a 10% "kicker charge" and the other 90% Black Powder. Others that are using SLOW military pull down powders will add this "kicker charge" to make up for the lack of flame in their smaller rifle primer. Some of the powders they use were designed to be lit off by primers that have as much "oomph" as a .22LR.

I have encountered some who load the venerable 45/70 in this manner. Some will use Bullseye as the kicker, then use a piece of toilet paper as a "separator", with the main charge a slow burning smokeless powder.

It is a process that can work OK at best and at it's worst, be a real disaster. Definitely not a practice for just anyone, especially when there are so many other safer selections.

 

[elsie]

Not recommended.

I recall once seeing a list of various powders sorted by their burn rate (it was quite a few years ago and I don't remember where). If you are looking to experiment with loads to give the results you describe, you could find more of a 'medium' burn rate powder. But I believe a lot of this experimentation has been done by the folks that do the load books.


elsie

 

[pinne65]

Don't worry, I'm not going to try this. Your responses were enough of a dispersuation. I was just curious. (Sometimes when someone says "Don't try this at home" I get this irresistible urge though ;-)

 

[deadshot2]

(Sometimes when someone says "Don't try this at home" I get this irresistible urge though ;-)

By the time I was 16 I figured out why that warning was given. Looking back I'm amazed I still have two legs, two arms, all my fingers, both eyes, and can still hear. Come to think of it, I'm amazed I'm still here, period.

 

[RVTECH]

Don't worry, I'm not going to try this.

Good - after reading your post I thought we were going to have to send the men in the 'funny white suits' to pay you a visit!

 

[RVTECH]

Come to think of it, I'm amazed I'm still here, period.

Me too - at about the same age I was the neighborhood 'Junior Chemist' and use to make home made hydrogen and acetylene. These two gases have something very unique in common........

 

[Velzey]

P O Ackley did it! And blew the heck out of allot of guns!

 

[deadshot2]

P O Ackley did it! And blew the heck out of allot of guns!

Hey, if you don't blow one up, you'll never know what the upper limit is

 

[Spitpatch]

Here, the consensus is the truth (not always the case). "Mixing" powders is NEVER a good idea. It could very well be your last idea.

Having said that, utilizing two powders in a case can be a very good idea. (Better than "OK at best"). I have experimented extensively (and used in practicality) with "Duplex Loading" for the .45-70, 44-40, and .45-60. The objective is twofold: a more complete ignition of blackpowder (or Pyrodex) toward more velocity consistency, and secondly for a markedly improved ease of cleaning the gun afterward. It is a practice that has been utilized (safely and efficiently) for over a century, and has garnered a huge amount of devotees.

The technique is much as described above, with a fast-burning powder of a small amount (enough to span the breadth of the case over the primer), and then topped with the bulkier, slower propellant to finish the entire charge. For the blackpowder cartridges, no divider (tissue or otherwise) is necessary to keep the substances seperate: these cartridges and propellants are best (and nearly always) loaded with slight compression of the powder charge. Nothing moves inside the loaded cartridge, and so the powders maintain their original positions. Unique is a favorite for the "starter charge", also IMR4759.

Blackpowder Cartridge competitions largely prohibit Duplex Loading, and so the widely used practice there (with similar results) is to use a Magnum primer to get complete blackpowder ignition. Some "experts" claim this is just as good as Duplex Loading, while the devotees of Duplex argue that contention (but adhere to the rules, and so therefore go the primer route). Off the circuit, they revert to what has worked so well for them.



Uberti Winchester Model 1866, Caliber .44-40 Win. Duplex Load: 5g IMR4759, 23.0g Pyrodex RS.

 

[PaulZ]

Thank you gentlemen. This is the kind of useful information we need here~!

 

[Kevatc]

I'm curious what would happen if you mixed fast and slow burning powders. The idea would be to prevent an early pressure spike and teetering coming from using only fast powder, and to prevent too much slow burning powder burning after it leaves the barrel. And ultimately be able to achieve higher velocities at lower maximum pressures.
Does this make sense, has anyone tried this?

I do this all the time. I pour about 4 different powders and mix with the wifes coffee grinder ... by candlelight. I then reload while smoking and lighting up with a acetylene torch. I haven't blown myself up .... yet. M guns haven't faired as well.

All kidding aside I think it's best to choose a powder that works for you. And don't weld while reloading.

 

[bhuch5]

I was once given a nearly full can of IMR 4350 for my 30-06. I loaded my usual load (quite conservative) and went to sight in. The first round bucked "HARD". I could not get the bolt open and wondered what the heck had happened.(first issue in 35 years of reloading) I had to beat the bolt out with a rubber mallet. The back tore off the case and there was no visible headstamp left on case. Excessivie pressure for sure. Getting the rest of the case out of the chamber was a chore.

The first thing I did was tear down all my loads to weigh the charges. While the charge weights were dead on I noticed that there were from 2 to 14 flakes of flat flake powder in several of the loads (looked like UNIQUE). I figure the powder I received was accidently mixed with a fast pistol powder before I received it and not noticed. There was really not much pistol powder in the entire can (maybe 20 Grains in weight)and I can only guess at how many flakes were in the round I fired.

I felt fortunate that neither my rifle nor myself suffered any harm that day.I now check all powder (even new cans) for content before use.
Moral of the story . . . NEVER MIX POWDER TYPES.

nuff said, Bruce H

 

[Spitpatch]

Moral of the story actually is, be VERY suspicious of ANY cannister of powder you did not purchase new and sealed. I look at the various partial cannisters of powder for sale on gunshow tables much as I would view a coiled rattlesnake.

 

[deadshot2]

Moral of the story actually is, be VERY suspicious of ANY cannister of powder you did not purchase new and sealed. I look at the various partial cannisters of powder for sale on gunshow tables much as I would view a coiled rattlesnake.

If the price is right, it makes pretty good fertilizer Either that or some rather spectacular "sparkle buckets" for the 4th of July. Pour it in a steel bucket, add some of the particles that accumulate under the grinder or from the local shops brake lathe, and then just use a long piece of cannon fuse. Stand back and watch the show.

 

[Jerzy]

I'm curious what would happen if you mixed fast and slow burning powders. The idea would be to prevent an early pressure spike and teetering coming from using only fast powder, and to prevent too much slow burning powder burning after it leaves the barrel. And ultimately be able to achieve higher velocities at lower maximum pressures.
Does this make sense, has anyone tried this?

For a little mental exercise, think about how even the "mix" would be. Ever mixed peanuts and cashews? Peanuts and pretzels? For some darn reason, unless it's a substance dissolved in a liquid, they always separate or stratify. The small pieces to the bottom (quick burning) and the large pieces (slow burning) to the top.

The "Idea" is perhaps OK, there's just no way to do it and maintain a fully dispersed mixture.

The Powder manufacturers have had all their success from essentially layering EACH granule of powder. various methods of forming the granules, as well as their composition, gives you the best of all worlds or at least the best possible.

There is a practice known as "Duplex Loading". Some will use a "kicker charge" of a fast burning powder like Bullseye under the "main charge". This practice can be found among those with old black powder cartridges with a 10% "kicker charge" and the other 90% Black Powder. Others that are using SLOW military pull down powders will add this "kicker charge" to make up for the lack of flame in their smaller rifle primer. Some of the powders they use were designed to be lit off by primers that have as much "oomph" as a .22LR.

I have encountered some who load the venerable 45/70 in this manner. Some will use Bullseye as the kicker, then use a piece of toilet paper as a "separator", with the main charge a slow burning smokeless powder.

It is a process that can work OK at best and at it's worst, be a real disaster. Definitely not a practice for just anyone, especially when there are so many other safer selections.

Nobody said that they must be dispersed.
But a layered arrangement of several different powders in artillery shells was succesfully used by Germans in WW2.
After the war I have seen a few open small artillery shells (~50mm-100mm caliber). The shells were cylindrical and looked like gigantic 22 bullets. Each shell contained a few leyers of different powders separated by hard paper discs. Since the shells did not have necks it was relatively easy to preapare such loads by puting the proper powders and sequencially pushing in the separating discs.
The grains next to the primer were small, the lowest level was similar to a very coarse rifle powder. The grain size was increasing for layers further away from the primer and they had more and more pierced channels through the grain. The top layer was filled with a very large cylindrical grains with diameter close to 4- 5mm and length of the grain close to 10mm, having many (6-7?) parallel pierced channels along the grain.
Germans were very practical. They would never do it without a good reason. And looking at that structure one can immediately see the reason of it. As the projectile moves faster and faster in the barrel there is a need for faster gas production if you want to keep pressure. For pierced grains with many channels the burning surface increases as they burn which gives the necessary greater speed of gas production.
So comments claiming that using a few different powders in one charge is a nonsens is inacurate.
Which does not change the fact that such an activity is damn dangerous if you do not know what are you doing. To stay safe you need a good theoretical model of burning powder and you can find that. In addition you need a good set of burn parameters for the powders you are planning to use and I doubt if you can find these. Several years ago there was a step made in that direction by assigning numbers to the burning speed of powders. Unfortunately, one number does not solve the problem because most of the powders today burn in a progressive way. In addition their response to pressure might be different. The numbers vanished and now we have tables where the powders are aligned "according to their speed" with no numbers quoted.
Jerzy

 

[po18guy]

About 1957-ish, one Dick Casull used a triplex load in .45 Colt cases, looking to make a ".45 Magnum" Certainly there were probably spectacular failures, but the .454 Casull resulted from it all. This was back when no one said "Don't try this at home."