Home Forums Reloading Big Game Rifles Is anyone using Duplex loads

JBLEDSOE,

It looks like a couple pages already and I didn't even get to play. Generally I am not concerned with what others think is or is not safe if they have not tried it. So I am not concerned here.

I did the tube in the case with my 7-.300 Weatherby. It barely helped in the velocity and was not worth the effort. Years later I had it rebarreled to .375 diameter.

When I first had my K14 rebarreled to .375-8 Rem Mag I could not get the velocity I wanted. I started using different powders in combination. I discovered if the faster powder is against the primer, it acts like the faster powder. If you put the slower powder against the primer, you get a higher velocity than either of the powders will produce without the bolt getting sticky.

I remember chronographing for a friend with a 7X57 shooting 175 grainers. I think they were about 2700, but I could be wrong. It's been dacades. Most certainly I remember the velocities of the 300 grain Sierras: 3000, 3006 and 3000 feet per second. My buddy casually asked,
"What grain are those bullets?"
"These are 300 Sierras," I told him. I can still remember his outragesou exclamation.
"Those are rinocerous bullets!"

But then MRP became available and ran the same velocity without all the work of carefully keeping the cases upright and away from the bench so I didn't load two shots of the wrong powder. Stick in 100 grains and go shooting. When that was illegal to import, I switched to RL22 and had to drop back to 98 grains. The velocity fell off a little, but was so close, I didn't want to fool with duplex loads anymore.

I hope this is fun to read. It is fun to remember that guy's emotional reaction.

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Ringman, Thank you for your very enjoyable post. I suspect that with todays excellent array of powders there is little to be gained with mixed powders outside of factory offerings. It was fairly common years ago when the variety of powder was so limited. I had hoped to hear some stories and adventures but heard mostly tirades as if I were asking for advice. I suppose that most people can't think outside the box.

Thanks anyway, Let's hear more!

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13579...

All good questions... wish I had equally good answers.

I'm not aware of any pressure testing on mixed loads.

My suspicion is that the problem with mixed powders is that with agitation, the powders will tend to separate. The way that I discovered AA9 is a mixture was that I noticed that as I poured powder into my measure, I saw streaks of gray and black. Under the microscope (IIRC) the powder contained round black spheres and gray oblongs. The streaks I saw during pouring were because the powder had separated somewhat. Now, I'm always sure that my AA9 is well mixed. I've had absolutely no problems, and I get very consistent loads from it.

I speculate that one reason for the strong warnings is that some fool might see that some cartridge works with 60 grains of H4831 or 50 grains of Varget, and try shooting a 55 grain mixture of equal parts of the two. That would instantly put the loader into uncharted territory.

Hodgdon has recently introduced a mixed powder where small granules of one type of powder are stuck to larger granules of another powder. That would solve the separation problem quite nicely.

For me, the whole duplex thing is pretty much uncharted territory. My only contribution is that I happen to have noticed that the two powders mentioned are both mixtures of two different powders, so obviously some shooters are shooting mixed powders and not knowing or worrying about it.

My previous post was from the Lynchburg VA airport. I'm home now, and exhausted. Tomorrow, if I have a litte time and energy, I'll shoot some microphotographs and post them.

It would be interesting to know if it has been tried under controlled, labotory conditions. There is a lot of speculation, but no one seems to know positively.

But even under controlled labotory conditions, there could be problems. Given all the different powders available today, and the many combinations they could be mixed in, in addition to the different amounts of different powders in different cartridges, you could come up with millions of different mixes.

Even choosing one cartridge, and all available powders, and varying the weights of the different powders, you could spend a lot of time just on that one cartridge. Still, if I had a pressure gun and lots of money and lots of powder, then I might...well, sometimes I get curious about 'what if' or 'what would happen.'

If I were going to do it, I think I would stick to compressed loads, or at least use a filler. There would be less likelyhood of the powders becoming mixed.

Pure speculation here, but I think what denton reports as two kinds of powder mixed is actually the result of the factory blending in a proportion of granules with or without deterrent coating to achieve a burn rate target. It's the same powder, from the same batch, but some of it is held aside before the deterrent coating step. But again, that's speculation.

I have seen cans of powder where some of the kernels were spherical and some were flattened. But before the flattening, I suspect it was the same batch. Again, I believe this is the result of blending to achieve a target specification.

If there is blending within a canister to achieve a burn rate target, what is to keep the proportion correct from case to case when it is loaded? I could easily be missing something here. (My wife claims that I usually miss a lot.) Always in appreciation of explanation, John

one has to ask whY????

I was aware of one local nimrod who did that.. and managed to destroy 3 actions in 6 months, playing with it...

I also use to have an uncle that would put a cherry bomb between his teeth, light it and then spit it out to explode before it hit the ground... the family always thought he wasn't all there either....

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When one is as old as I, one need not ask, one knows. When dirt was young powder selection was limited to Black and a half dozen smokeless varieties. If a burn rate was to fast/slow the next powder was the opposite so some shooters would mix powders to speed up or slow down the burn rate. No need to mix powders now days we have several to fill any need. So does that mean we cannot show an interest in some of the old experiments? Pardon me while I put on my blinders.

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JB:

Please don't interpret my post as slamming your question or you...you are a good man.. If you took it that way, please accept my sincere apologies..

I have seen folks not knowing what they are doing, mess up stuff doing that.. luckily no one hurt too bad...

however all it is done for is to try and gain more velocity.. and the way I see it.. if you have an 06 and think you need a 300 Weatherby.. either trade the rifle, replace the barrel and rechamber...

but since 95% of all game is taken at less than 200 yds, I am usually at a loss for the logic of magnums or more velocity..
several clicks on the scope settings will usually compensate for point blank range differences of 200 fps or more...

Seafire,



You are sorta correct here. Sorta. When I was doing the tube thing, I was looking for longer barrel life. I already was shooting a 7-.300 Weatherby. When I rebarreled and chambered it to the .375-.416 Rem. I was just playing when I put one powder on top of another.

I nevered used duplex loads in my Freedom Arms, and yet I still ran it up to max and then some. I also ended up with a bullet stuck in the bore from trying to see how slowly I could make them go. Some folks just like to play. When you play like this, you pat the 'smith.

Back when I was making duplex loads in my .375-.416 I never heard of clicks in a scope execpt when sighting it in. Even prior to that, I sighted in my first hot rod, a .308 Norma Magnum, at 225 yards. That way I could shoot WAY out there to 300 without hold over.

Now I have a 7 RUM and can shoot to 400 on an elk without hold over. Times change.

If it wasn't for the politcal climate of the day, these would be the good old days.

JB:

I don't think anyone really knows for sure, or maybe the ones who actually tried it did not survive the experiment.

It would seem to me that the only people who know for sure whether or not it is feasable would be the powder manufacturers, and, to my knowledge, they are not talking.

I don't think anyone is trying to give you a hard time. My opinion is that at best, no one actually knows, and at the worst, any opinions are only guesses.

I read somewhere, I can't remember where, about someone putting live primers in the cartridge, along with the powder. My question was, had anyone else ever heard of this?

You would have thought, from the repsonses I got, that I was going to mix thousands of pounds of powder with hundreds of thousands of live primers and blow up half of this part of the world. I got the impression that some of the readers of this forum were going to gather up all their wives and children and leave for another part of the world, where there were deep holes they could hide in, and that I would soon be declared a menance to society, and all I did was ask a simple question.

Don't be put off by some of the answeres you get. I think some posters read the question, if they read it at all, only after they have written their response.

odds, I remember the bit about primers in the case as well. I am not sure, but it may have been Charlie O'Neill. Seems like I remember the same guy also useing a loaded 06 round as the "bullet" in one of the large cases. Like you, I am neither contemplating nor advocating doing any of this, but I am somewhat fascinated by what people have tried in the past (and sometimes even survived).

5sdad:

"but I am somewhat fascinated by what people have tried in the past (and sometimes even survived)."

I don't want to hijack this thread, but do you remember reading about the double barrelled canon the South built during the cival war? It was supposed to use two canon balls connected by a length of chain, and the theory was the two balls would stretch out the chain and it would be kind of like a chain fence mowing down enemy soldiers.

The problem was, when it fired (the only time), one ball came out a little bit before the other one, and they whirled about on the end of the chain. It tore up fences, IIRC, a field of corn, and a bunch of more stuff as the balls whirled around, before they finally stopped. Someone else tried making a canon barrel from a hollow log, but that didn't work, either.

A few years ago, here in Georgia, a hunter was killed by an exploding muzzle loader loaded with smokeless powder.

I remember the double-barreled Civil War cannon. Seemed like a good idea, but the timing was the problem, as you point out. Must have been exciting to witness its firing. On Mythbusters, they had the same problem trying to ignite two rocket motors at the same time in an attempt to get a dummy to go over the top of a swingset. Best, John

With only recoil to go by since chrony's were still a ways off for most of us, The 50/110 with about 40 grains of FFFg in the bottom and topped off with enough FFg to slightly compress the charge with the Lyman hard cast, 505 grain slug, the load was WAY better than any non-duplex load we tried.

Wayne

Yes...I have experience with duplex and tri-plex loads and if you want some recent information go to Accurate Reloading - Big Bore - 12GAFH thread...there are a few individuals that still do it...it is still related to large cases, large amounts of very slow burning powder and trying to get the maximun results...highest velocity and greatest impact energy.

I experienced one destroyed receiver...but that could have been caused by many factors not limited to but incuding the duplex load...these were experiments by individuals pushing the envelope...I was more a bystander, young and just learning the trade and more of a gofer boy than anything else...it still impressed me enough to not experiment any more with these types of proceedures in the ensuing 40 some odd years...there are any ways to arrive at a solution to a problem and because of so many factors that I won't list. I always look for and find the simplest and least complicated...and those doing the experiments were cognizant of the of the possible results that some safety steps were taken...just in case...no one was hurt in any of the experiments...only equipment...that is the difference between experimentation and screwing around...planning and preparation, evaluating the parameters and accepting the consquences with a goal in mind...

These types of loads were used way back in the day, mostly by wildcatters or experimenters trying to reliably ignite large amounts of very slow burning powder in large cases with light to heavy bullets and trying to get the highest velocities possible.

I don't see any need for du/tri-plex loads in todays world except for those developed for a specific purpose by a munitions factory...besides there are many powders and priming compounds used by the factories that aren't available to the reloader...for many very good reasons, not the least of which is MONEY and PROFIT....

Today we have a wide range of very good powders and primers that pretty much preclude doing these types of activities except for the very, very experienced experimenters...for very narrow applications...

Most of the problems surrounding du/tri-plex loads centered on keeping the priming mixture in one place and we tried all kinds of "stuffings" and "packings" from tissue paper to thin overpowder cards to waxed and ironed silk cloth...nothing worked as far as something useful in the field...shaking the case in pretty much any way would displace the priming powder and you would get various ignition sequences including click...silence...and pressure and velocity variations. Triplex loads were the most dangerous...think about how hard it is to keep 3 different powders in contact without mixing...not very easy...plus the fact of an air gap between the different mixtures...and the possiblility of a secondary explosion rather than a quick burn...even though powder burns very fast, it still burns...it doesn't explode...except BP which does explode...BP was also tried without any success.

If you're smart you WON'T do mess around with this process in anything but a controlled laboratory setting....it's not worth the possible results.

There is a hellofalot of difference between a powder maker mixing powders to achieve a specific burn rate and some dumass mucking about mixing this and that and thinking he is coming up with Gods gift to reloaders...that should be very appearant to the average reloader, but it never stops some people from doing it.

JB...you've posted many times before....you should know by now that asking ANY question on ANY forum could bring out the rowdys and you will get a wide range of replies...it is basically the question of "if you can't stand the kitchen...don't be going in there"...no flame intended...I get the same BS all the time, mostly from mindless [bleep]'s...sometimes I wish this medium was "feelavision" not television...that way I could reach through the screen and take care of the problem...permanently... We humans are what we are, got where we are today because we are a dangerous, aggressive species with a highly developed brain and a grasping, opposed thumb hand and the capability to destroy ourselves...doesn't matter if it is on a forum or in a lab developing weapons of the future.

You were/are a very long way from knowing that the resulting mixture will have a burn rate inbetween the two starting powders. It may, or may be faster than either, or slower than either. The point is you have no way of knowing.