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Mixing Different Powders Together

We do duplex loads a lot with smokeless muzzloaders. I use an H322 main charge over a IMR4198 booster. Of course, we're standing on the shoulders of a couple guys who invested in pressure trace equipment and did extensive testing. The duplex gets me 200fps over what can be achieved with a single powder.

I don't remember all the details from Doug's Savage Board (the data is stored there), but I do recall some combos which produced a second spike when the bullet was hear the muzzle -- the type of thing that has led to some muzzle sections separating in military applications, from what those there with personal experience shared. So personally I stick in the conservative zone of the loads which were developed there with real pressure trace data and shown to be safe.

A number of triplex loads were tried. Those tested produced no advantage over duplex loads.

On an anecdotal basis, a couple guys mixed their powder rather than layering and noticed no difference. YMMV.
 
No difference as compared to NO blending whatsoever, or no difference as compared to the stratified duplex load?

No difference in velocity comparing mixed to stratified. I do not recall for sure if pressure traces were run on the mixed load. The data is all archived on the site.
 
Old thread I know... but one this came up in my research. I was wondering how this turned out. The reason is not for any velocity gains, but for safety concerns. Because damnit I accidentally dumped a little Reloder 17 into a tub of Reloder 16. I’d guess the mixture is about 1 part 17 to 10 parts 16, maybe even less 17. And it’s about three pounds total I’m guessing. Too much to just throw out if safety was not a concern. I can’t tell the difference looking into a bowl of the mixed powder, they both look similar. So I’m wondering if anyone has any experience with this. Would be for 6.5x47 if that makes a difference. Flame away if this is just dangerous penny pinching, but I’m really curious and would like to hear from anyone with actual experience if it exists.
 
Old thread I know... but one this came up in my research. I was wondering how this turned out. The reason is not for any velocity gains, but for safety concerns. Because damnit I accidentally dumped a little Reloder 17 into a tub of Reloder 16. I’d guess the mixture is about 1 part 17 to 10 parts 16, maybe even less 17. And it’s about three pounds total I’m guessing. Too much to just throw out if safety was not a concern. I can’t tell the difference looking into a bowl of the mixed powder, they both look similar. So I’m wondering if anyone has any experience with this. Would be for 6.5x47 if that makes a difference. Flame away if this is just dangerous penny pinching, but I’m really curious and would like to hear from anyone with actual experience if it exists.
Start low and work up like with any new powder and I bet you will be just fine. I’d make sure I turned the jug over enough to try and evenly disperse it. But I wouldn’t want to throw out 8 lbs either.
 
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I'm interested in having an intelligent discussion about mixing/blending powders.

If all you have to say about it is "Don't", please save it.

If you can qualify the "Don't do it" with rationale and reasoning, I'm all ears.

I know for a fact it is common practice for big cartridges, such as 460 Weatherby and 500 A-squared, to drop 5-10gr of a fast pistol powder in the case on top of the primer, followed by a heavy charge of slow rifle powder. Usually this is only for compressed charges, to keep the pistol powder by the primer, and not get mixed throughout. They call this a duplex load.

I'm more interested in the idea of blending two fairly alike powders together, so wind up with something in between.

Say you're loading for a cartridge that works well with Varget and H4350, but Varget is a bit too fast and H4350 is too slow. What would happen if you mixed the two 50/50? Speaking theoretically, so as to assume you had a homogeneous (NOT STRATIFIED) charge, would you in fact end up with a burn speed between the two?

Seems to me you would, though I'd expect it to be closer to the faster powder if mixed 50/50, because the slower powder would burn faster than normal on account of the faster powder present, and the higher pressure...?

Either way, I don't see how a 50/50 mix of Varget and H4350 would burn faster than just Varget alone. Thoughts?

It seems it would be safe to start at a charge weight known to be safe with the faster powder.

Bottom line: if Varget is safe to use, and H4350 is safe, how could the two mixed not be safe?

I know I've read posts from chemical engineers here on the hide commenting on burn chemistry...hopefully one will chime in and educate me.

Thanks!

I have three lots of Varget. One produces about 2650, one 2700, and one 2750 with the same charge weight.

I did an experiment where I mixed equal amounts of the fast and the slow lot which produced 2700.

I don’t see a problem mixing like powders where there isn’t any potential for negative interaction with the different chemicals. But I would not mix different brands or pistol and rifle powders, or single base with double base.
 
Mixing different lot numbers of the same powder is a different animal than mixing different powders. The only thing I will say is if you do attempt it you better mix it throughly. Beyond what you think is reasonable. If you get a charge that is 80% 1 type just by dumb luck things will change...
 
I had 1 granule of IMR4350 in a single round of a batch that was filled with H4350, won't bother with why, it's stupid. Anyway, 49 rounds went just fine with no pressure signs. That one blew the primer completely out and stretched the primer pocket out, had to beat the bolt open with a hammer. So... if you're not equipped with a pressure testing rig, and you have no expertise in the field and you're not trained in some kind of applied science, don't do it.
 
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There's no problem mixing powders, until there is a problem--which might cost you your eyes, fingers, face, etc. Has always seemed like a really dangerous move with absolutely no upside. If you have a little extra powder, throw it on your lawn or load a couple fouling shots.
 
I had 1 granule of IMR4350 in a single round of a batch that was filled with H4350, won't bother with why, it's stupid. Anyway, 49 rounds went just fine with no pressure signs. That one blew the primer completely out and stretched the primer pocket out, had to beat the bolt open with a hammer. So... if you're not equipped with a pressure testing rig, and you have no expertise in the field and you're not trained in some kind of applied science, don't do it.
I’m not an expert but I’ll say it’s hard to believe 1 granule of a similar powder was responsible for that. Just doesn’t seem logical it could cause such a violent reaction with the other powder after combusting. I’d be interested to hear an expert opinion on it for sure...no offense if you are an expert in this then touché.
 
Why not; you ask...

Mixed powders tend to have inconsistent burn rates, round to round. This practically guarantees it to be impossible to get a good load. Trying to mix the powder to a true consistency screws around with the kernel deterrent coatings, and can alter burn rates considerably (usually making it faster), further complicating your task.

This also forces you to use them in an unnecessarily conservative manner for safety reasons, and thoroughly defeats the purpose of load development.

Unless you know precisely the proportions of powders, you can never duplicate a good(?) load once the original powder is gone.

Because charge weight ranges have minimums as well a maximums, the breadth of the safe charge weight band become smaller and smaller, until it's so limited it becomes unworkable.

Gunpowder is expensive, but never so expensive that holding onto an unknown product is worth the potential damage and injury that using it could provide.

Let's just suppose you die with that stuff on your shelf. The next person to try to use it may very well be unknowingly building a bomb. Helluva legacy, I say.

Dispose of that crap, safely.

I've been handloading since the early 1990's, and have occasionally had to develop loads for cartridges that were so new, most books didn't have data. That's hard enough to do safely when working with a propellant that is at least uniform granule to granule.

Trying it with differing granules is just slightly more dangerous than handing a loaded AK to a Chimp.

At least the Chimp is slightly less likely to blow something or someone up.

When you tell people in advance not to bother giving you intelligent, proven safety advice when confessing that you will be doing something that is universally accepted as something done only by people who are as dumb as a stump, you elevate the Chimp to become your intellectual superior.

Dispute any or all of this, most of it is long accepted truth. It is truth and if that truth hurts, maybe it damned well should. But there will always be those who consider themselves special and outside the rules for us regular folks.

Folks who deliberately ignore general safety regulations are doing dangerous things. I don't want them doing that stuff anywhere near me.

For goodness sake, at least remove the original labeling, and mark it prominently with what it is and that it is an experimental propellant.

Greg
 
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The pet load of the guy that designed the 454 Casull was a triplex load with a fast pistol powder, medium powder and slow burn magnum powder in a compressed load. Wonder how the hell he came up with that.
 
I was going to respond with a pithy comment about old/bold reloaders. But then I think hey it’s 2020, I need to get with the times and be less conservative.
So go for it! Take chances, make mistakes, be adventurous! Throw all of your reloading books in the trash, they’re really just a guideline anyway. Just mix all of your powders into on big bucket, cram as much powder into a case as possible and blaze away.
I only ask two things;
First, stay away from anyone/thing that doesn’t want to be killed/destroyed by you. (Namely me, stay the hell away from me)!
Second, take a lot of pictures/videos, because without visual evidence nothing happens. And you are not going to convince nearly as many people that you are right without evidence.
...


That was sarcasm by the way. If you accidentally mix powders, the responsible thing to do is fertilize your lawn. It is an expensive, yet valuable lesson that you need to improve your reloading skills, do that you don’t make that mistake again. Honestly if you are unwilling to take responsibility for your mistakes and do the right thing, then you shouldn’t be reloading.
 
I was going to respond with a pithy comment about old/bold reloaders. But then I think hey it’s 2020, I need to get with the times and be less conservative.
So go for it! Take chances, make mistakes, be adventurous! Throw all of your reloading books in the trash, they’re really just a guideline anyway. Just mix all of your powders into on big bucket, cram as much powder into a case as possible and blaze away.
I only ask two things;
First, stay away from anyone/thing that doesn’t want to be killed/destroyed by you. (Namely me, stay the hell away from me)!
Second, take a lot of pictures/videos, because without visual evidence nothing happens. And you are not going to convince nearly as many people that you are right without evidence.
...


That was sarcasm by the way. If you accidentally mix powders, the responsible thing to do is fertilize your lawn. It is an expensive, yet valuable lesson that you need to improve your reloading skills, do that you don’t make that mistake again. Honestly if you are unwilling to take responsibility for your mistakes and do the right thing, then you shouldn’t be reloading.


Thank you Spife, 918v, Spamassassin, and others for chiming in. I just figured I’d ask because the easy answer is to dispose of it, but I was wondering if anyone had actually used these two powders in a mixed batch. Been reloading for a long time, my first log book is marked 11/23/03 for load #1, and I’m on load # 1360 now. That’s 1360 different cartridge/load combos, so I’ve been around the block with reloading. Anyway I just thought I’d ask because even though I’ve always heard the mantra “Don’t Mix Powders!” and have never done so, I do know that’s it has been done. And due to the two burn speeds and their ratios, and the fact that both are ok in a x47, I figured that just maybe it would be safe to start low, but who knows? I’ve heard everything from the “one mixed grain will destroy you” to the “I know a guy who does it all the time”. So I do not think there is an absolute truth to never mixing powders, but you don’t know what you don't know, and things like secondary pressure spikes should certainly be avoided. Anyway this powder would be regulated to low pressure plinking rounds if I find it safe, but that’s the catch.

And Go Cougs and Greg Lengelius, if I decide to actually try it, it would be in a manner that would not endanger myself or others. But very possibly the equipment. And that is why I was wondering. Merely wondering. That should go without saying, but common sense ain’t so common I suppose. Anyway, if I decide to try it I will report back with the results. Thanks again.[/QUOTE]
 
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I’m not an expert but I’ll say it’s hard to believe 1 granule of a similar powder was responsible for that. Just doesn’t seem logical it could cause such a violent reaction with the other powder after combusting. I’d be interested to hear an expert opinion on it for sure...no offense if you are an expert in this then touché.
I assume you're familiar with catalysis? If not, look it up and your surprise will wane. If you needed lots of something mixing with lots of something else to make a violent reaction happen then there'd be no such thing as organic life on this planet. Catalysts speed up reactions. The ones in our cells are speeded up by a million or a billion or even a trillion times. Catalyzed reactions can be incredibly violent.

I was pretty GD surprised too but it in fact happened and I suspect catalysis is the reason for the violent increase in pressures. I know it happened because it happened to me and I know it was 1 granule because I deliberately put exactly 1 granule in the case. The reason might be now helpful: The reason for doing this was that I'd screwed up and poured some IMR-4350 into a bottle of H4350 and, knowing there was no way to 100% separate the two (they look too much alike to be certain), I wanted to see what might happen if I were to use that bottle. The bottle was at that point about 12% IMR-4350 by weight and I was thinking it couldn't be that big a deal. So, I took 1 granule of IMR 4350 and and put it in a case I'd already charged with a normal charge of H4350 and then seated the bullet and gave the case a good shake to randomize the position in the powder column that the granule ended up in. I figured if nothing bad happened I'd do the 1 granule test with it placed at top, at bottom, middle and see if there is positional sensitivity. Then if nothing bad happened I'd planned to move up to 2 granules and on and on towards 12% of total charge (that would have been about 140 granules) to see if/where things get funky. Never made it to 2 granules. Things got funky immediately.
 
I assume you're familiar with catalysis? If not, look it up and your surprise will wane. If you needed lots of something mixing with lots of something else to make a violent reaction happen then there'd be no such thing as organic life on this planet. Catalysts speed up reactions. The ones in our cells are speeded up by a million or a billion or even a trillion times. Catalyzed reactions can be incredibly violent.

I was pretty GD surprised too but it in fact happened and I suspect catalysis is the reason for the violent increase in pressures. I know it happened because it happened to me and I know it was 1 granule because I deliberately put exactly 1 granule in the case. The reason might be now helpful: The reason for doing this was that I'd screwed up and poured some IMR-4350 into a bottle of H4350 and, knowing there was no way to 100% separate the two (they look too much alike to be certain), I wanted to see what might happen if I were to use that bottle. The bottle was at that point about 12% IMR-4350 by weight and I was thinking it couldn't be that big a deal. So, I took 1 granule of IMR 4350 and and put it in a case I'd already charged with a normal charge of H4350 and then seated the bullet and gave the case a good shake to randomize the position in the powder column that the granule ended up in. I figured if nothing bad happened I'd do the 1 granule test with it placed at top, at bottom, middle and see if there is positional sensitivity. Then if nothing bad happened I'd planned to move up to 2 granules and on and on towards 12% of total charge (that would have been about 140 granules) to see if/where things get funky. Never made it to 2 granules. Things got funky immediately.
I understand catalysts. Look at airbags. I’m also not doubting your experience. My point is, it’s hard to believe companies would produce something that’s so violent and potentially dangerous that 1 granule would do that. That’s all.
 
But those companies also tell you not to mix powders.

Reloading is not like pouring cereal and milk in a bowl. It is a process that requires specialized knowledge and skill. Reloading components are not consumer items.
 
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In the interest of your safety, I'll go a bit further on below minimum charges.

There is a term known as secondary explosion effect. This phenomenon is a real danger, and I would be remiss in not bringing it to your attention when you are talking about low pressure plinking rounds.

For the sake of discussion, I would term 'slow powders' as powders slower than pistol or shotgun powders.

For my own purposes, I try to reserve 'Unique" for all of my sub-standard power loads.

Be safe;

Greg
 
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I understand catalysts. Look at airbags. I’m also not doubting your experience. My point is, it’s hard to believe companies would produce something that’s so violent and potentially dangerous that 1 granule would do that. That’s all.
I hear tell that there are 10's of thousands of places where you can drive up and fill whatever flimsy container you bring with an extremely flammable liquid with little or no supervision or warnings whatsoever. Heck, if you go to Kroger's I'll bet you find bleach and ammonia right next to each other.

I'll just echo what @918v said. This isn't making breakfast. It's making controlled explosions that we plan to have go off right next to our faces.
 
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I'm interested in having an intelligent discussion about mixing/blending powders.

If all you have to say about it is "Don't", please save it.

If you can qualify the "Don't do it" with rationale and reasoning, I'm all ears.

I know for a fact it is common practice for big cartridges, such as 460 Weatherby and 500 A-squared, to drop 5-10gr of a fast pistol powder in the case on top of the primer, followed by a heavy charge of slow rifle powder. Usually this is only for compressed charges, to keep the pistol powder by the primer, and not get mixed throughout. They call this a duplex load.

I'm more interested in the idea of blending two fairly alike powders together, so wind up with something in between.

Say you're loading for a cartridge that works well with Varget and H4350, but Varget is a bit too fast and H4350 is too slow. What would happen if you mixed the two 50/50? Speaking theoretically, so as to assume you had a homogeneous (NOT STRATIFIED) charge, would you in fact end up with a burn speed between the two?

Seems to me you would, though I'd expect it to be closer to the faster powder if mixed 50/50, because the slower powder would burn faster than normal on account of the faster powder present, and the higher pressure...?

Either way, I don't see how a 50/50 mix of Varget and H4350 would burn faster than just Varget alone. Thoughts?

It seems it would be safe to start at a charge weight known to be safe with the faster powder.

Bottom line: if Varget is safe to use, and H4350 is safe, how could the two mixed not be safe?

I know I've read posts from chemical engineers here on the hide commenting on burn chemistry...hopefully one will chime in and educate me.

Thanks!
This reminds me of my first college chemistry lab, where I caused and actual real explosion, fun day
 
So, I took 1 granule of IMR 4350 and and put it in a case I'd already charged with a normal charge of H4350

I'm calling BS on this. I wonder how many people refilled their hopper and left 1 or 2 granules of something different in it or a couple stuck in a powder funnel ledge... If something like this was remotely possible... powder manufacturers would have WARNINGS everywhere to avoid it.
Perhaps you were so worried about possible effect of mixing two versions of 4350 that you didn't notice you actually threw double charge?
 
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I'm calling BS on this. I wonder how many people refilled their hopper and left 1 or 2 granules of something different in it or a couple stuck in a powder funnel ledge... If something like this was remotely possible... powder manufacturers would have WARNINGS everywhere to avoid it.
Perhaps you were so worried about possible effect of mixing two versions of 4350 that you didn't notice you actually threw double charge?
Yeah I dont see 1 granule of a similar-ish powder doing much.

I load 6.5CM and it would be impossible to double charge the case with H4350 - at the upper end of the loads it is pretty much compressed.
 
Another resource for folks who want to look at duplex/triplex loads is Graeme Wright's book on shooting/loading for double rifles:


Obviously focused on big double rifle cartridges, and written by an Australian (where duplex and triplex loads are apparently more common) with access in some cases to different powders, but might be useful for folks interested in the topic, whatever your individual risk aversion level.

I'm not advocating mixing powders, but I'm also frightened by the fact our society has generated a charity to provide inner city kids with bike helmets. Really? We're up to bike helmets on Maslow's hierarchy of needs for those poor kids?
 
I'm not advocating mixing powders, but I'm also frightened by the fact our society has generated a charity to provide inner city kids with bike helmets. Really? We're up to bike helmets on Maslow's hierarchy of needs for those poor kids?
Give a kid a helmet and force his parents/guardians that can't afford a bike to buy one for them.

Seriously though I would love to hear from anyone who has tried this personally. I'm not willing to try it as of yet, read as probably never, but the information is always useful.
 
Prerequisite purchase to mixing powders: Pressure test barrel

That said, I've seen some preliminary stuff that suggests that it doesn't really matter what order you put the stuff in the case (fast/slow vs. slow/fast vs. mixed). What does matter is that you get the same ratio every time or else velocity spreads will go a bit wonky.

On a larger scale it's best to mix powders of similar/same kernel size so that one size doesn't settle out of the mix. On small scale stuff if you weight out 20gr of A and 40gr of B and put that 60gr mix into each case on a one-by-one you're set.

Again, though.... Wouldn't do it unless you can pressure test it and have a pretty detailed knowledge of what the available powders are and which ones are compatible with each other for mixing. Ammo companies do it all the time. Not really a great strategy for the at-home reloader IMO.
 
Interesting topic to say the least. I'm interested in developing a subsonic and quiet load for my 300blk suppressed. This forum has given me some very interesting ideas. I'm not afraid to experiment yet have complete confidence using common sense determination. Thanks guys!
 
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There is a lot of info here, some good and some bad.

One thing people need to remember is that a MSDS or SDS may or may not list all of the chemical compounds in a powder. Only those that are a hazard must be listed. As for what's not list, who knows.

Single base extruded powders control burn rate predominately with geometry using grain size and some chemical deterrent. Most small arms extruded powders have a hole in the middle and are considered progressive burning, the surface area increases as the powder burns. Double based spherical are digressive as the surface area decreases as the kernel burns. They primarily control burn rate with chemical deterrents.

I have read of powder mixing in cartridge/projectile development in literature to get a specific case fill/burn rate but this done in a lab/test environment. It's not a backyard let's see what happens. Stacked charges have been used but that usually required a filler to keep the powders from mixing.

I would recommend reading Ammunition Demystified by Jeff Siewert for more information on powders. Another is Ammunition Making An Insider's Story by G. Frost.
 
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