Duplex Powder Loads

[David Wile]

DUPLEX LOADS

MODERATOR INSERT--
This insert does not alter in any way member David Wile's post but I need to get this at the very top of this string. I will add comments toward the bottom.

The topic of this string is very controversial and HAZARDOUS. Mixing or blending of powders and/or "DUPLEXING" of powders in handloading is universally condemned in reputable loading manuals and references. Occasionally, some magazine will publish an article with profuse cautions amounting to "DON'T TRY THIS YOUROWNSELF!!!"

I don't know how I missed reading this string until it was brought to my attention by another staff member. For now, I will resist the urge to wipe out this whole thread, because I believe the original question was posed in a sincere quest for information, and not in advocacy of actually DOING this ill-advised activity.

CAUTIONARY NOTE: NEITHER THE ADMINISTRATION NOR THE STAFF OF THE FIRING LINE TAKES ANY RESPONSIBILITY FOR ANYONE'S EXPERIMENTATION ALONG THESE LINES. DO NOT DO IT!

I now return you to Mr. Wile's original topic opener - - -

Thank you,
Johnny Guest
H&R Moderator
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Hey folks,

I may have been reloading for a long time, but I have never mixed two different powders in one load, and that is what I understand is called a "duplex" load. This came up the other day when I was talking to someone about military surplus powders. I mentioned that I had tried WC-852, a slow ball powder, in my Marlin Cowboy 45-70 with a 405 gr cast bullet. I said that the powder did not seem to burn completely. In fact, after shooting a WC-852 load, the ejected round still contained a good bit of what appeared to be unburned powder granules, some of which would be deposited in the action and more would fall out with the ejected cartridge. There would also be a lot that obviously blew out the end of the barrel. Whether this was truly unburned powder or just burned powder residue, I am not sure, but I never noticed any when used in 30-06 loads.

The fellow with whom I was speaking suggested replacing seven or eight grains of the WC-852 with four or five grains of IMR 4198 to get a better burn from the WC-852. I seem to remember reading about duplex loads many years ago, but I never had any reason to use them, so the information seems to have spilled out of my memory banks. Does anyone have any experience in this area? I would like to reload some of the information back into my memory bank.

Thanks much,
Dave Wile

[DAVID NANCARROW]

A duplex load, as I understand it, is two projectiles in the same cartridge case. I have no knowledge of mixing powders in a case-it sounds dangerous and I have read time and time again never to mix powders, as the resultant combination is not predictable. Seems to me that you're using an older, dirty burning powder in comparison with the so called latest and greatest. I suspect there are those who reload for the 45-70 who could give you some guidance on what burns clean for your particular application.
I suspect that while WC 852 is a fine powder for the 06 and possibly for the 308 (no reloading books in front of me, so not quoting gospel here), the reason you may be finding unburnt powder in the action and case is because the powder does not have sufficient pressure to burn correctly.

[Ala Dan]

The late and great Mr. Elmer Keith did it, when experimenting
with heavy .44 magnum handgun load's; but I've never done
it, and don't recommend it. I too, believe this practice would
be far too dangerous?

Best Wishes,
Ala Dan, N.R.A. Life Member

[griz]

A Duplex load is a two powder load. I didn’t know Keith used them but when the 454 was being developed they tried Duplex loads. The theory is to get the bullet moving with a slow powder, then fill out the pressure curve with a fast powder to get more velocity. Apparently some of the big guns (big as in fired with a lanyard) do this successfully. When tried at the handgun level, there are problems with the powders mixing and its generally much more trouble than it is worth.

Short version, don’t try it.

[dick w. holliday]

i shoot a little black powder in my 45-70 and on some of the black powder boards i see mention of shooting black powder with a 10% charge of something else at the bottom of the case--it gives them less fouling--but i figure if i wanted to smokeless then i'd be shooting smokeless....Dick

try here for a bunch of good read on the 45-70 and all them ole timey bullets http://talk.shooters.com/room_14/topics.cfm

[BigG]

What it sounds like to me is that your load was a little light and didn't create enough pressure to burn fully. If it was a light load, you might try pushing a tuft of dacron pillow stuffing (available in notions dept. of Walmart, Kmart) atop your powder charge before seating the bullet. That will keep the powder back against the primer and ensure good ignition. The dacron completely consumes and leaves no residue.

I used to use that trick in my .458 Magnum when I loaded it to 45/70 levels with the 405 gr lead bullet. HTH

[Jim Watson]

Duplex loads with a priming charge of a LITTLE smokeless under a case full of black are a legitimate application. If it was good enough for Harry Pope, it is good enough for me. But you might have to be as smart as Harry Pope to make it work. Note that the powders are never mixed, the smokeless is held right over the primer by the compressed charge of black.

Duplexing of smokeless is a risky experiment. I don't know the casualty rate when Elmer Keith did his work on Double Duplex loads, but Casull blew up several guns with duplex and triplex loads. By the way, a Keith Duplex load only has one grade of powder, its gimmick was a tube from the primer pocket flash hole forward so that the powder would burn from front to back and not push an erosive plug of burning powder down the barrel behind the bullet. Theoretically, anyway, but he did report the familiar 202 fps increase in .50 BMG. Double Duplex was two powders plus the flash tube.

Dave, my recommendation is to load the .45-70 with an appropriate charge of the 4198 and save your 852 for the .30-06.

I am sure somebody will come along and tell us how great HIS duplex smokeless loads are, but I am willing to leave them to him. There are too many powders with tested loads to choose from for me to do uninstrumented experimentation at 50,000 psi.

[Keith J]

Duplex loading with modern propellents is quite unpredictable. Blackpowder works fine as all loads are over 100% density. Do it with less and the unknown mixing will introduce another variable in the mix, something contrary to common ballistics sense.

IMHO, WC852 is too slow for the case volume of a .45-70. I'm recommending you check out Lyman's complete reloading manual as there is a wealth of loading info for this cartridge tailored for the various actions. It includes black powder duplex loading as well as the Dacron filler applications.

[KP95DAO]

Once again people are expounding on that which they know little or nothing about.

Almost all (the exception being target 9mm and 45ACP loads) of my loads are made using blends of two different powders.

WC852 happens to be one of the powders used in my rifle loads. The powder used to blend with it is PSA.

I have fired many (over 20,000) rounds using blended powders. I started out using 4831 with a booster charge of Red Dot in a 44 mag. It worked. After much experimentation I gave up using "duplex"(that is two powders loaded seperately) loads in favor of blending to meet my burning rate requirements.

With this you can taylor your loads to your components and your gun and achieve this at much less cost. With two powders, ie. WC852 (slow lot) and PSA you can load everything from a big belted magnum with a heavy bullet to a 223 with a light bullet. And the powder will be correct for every combination.

I have been meaning to put this together for posting and haven't gotten around to it yet. I will do it soon.

JG and I have discussed this and, with the proper warnings, he has no problems with such a post.

My study of Col. Earl Naramore's book led me to this path.

One more thing. Most of you are using blended powders, it's just that the powder companies do your mixing for you. Perhaps it is time you learn to do it for yourselves. Soon.

[Ben Shepherd]

There was another thread on this recently, try doing a search.

By the way, the 454 Casull was originally a TRI-plex.

IF you do them(I won't), they MUST be a load that ends up with slight compression to keep the powders from mixing.

The other definition of "duplex load" is using a small tube threaded into the flash hole. This way when it lights off the powder starts burning in the middle, supposedly to keep the heat out of the barrel.

[Mike Irwin]

Duplexing, and even triplexing, loads is more akin to black magic than it is anything else.

The results can be unpredictable, but if you get to where you need to be without causing damage, you're usually OK.

It's just that getting to where you need to be point that's the iffy part.

[Mike Irwin]

KP,

There's a significant difference between the blending that powder companies are doing and the blending that you're doing.

The blending that powder companies do is to blend lots of the SAME powder to achieve repeatable burning characteristics.

Blending of dissimilar powders is, to the best of my knowldege, NEVER done for powders that are sold on the reloading market.

[Walt Welch]

Making Duplex loads by mixing two smokeless powders, a small charge of a fast powder being loaded first, then a charge of a slower powder, was something tried mostly in metallic rifle cartridges 40 or more years ago. It was found to be a dangerous and unpredictable practice. Today, magnum primers ignite the slowest powders adequately.

Mixing powders together to 'tailor' loads is something I wouldn't even consider. No consumer has the ability to do the quality control and pressure testing that an ammunition manufacturer has.

I condemn either practice.

Walt

[Gewehr98]

It may be considered "cheating" for SASS purposes, but my .45-70 Rolling Block is happiest with a few grains of WW231 underneath the main FFg blackpowder charge. Very clean-burning!

[C.R.Sam]

Multiple meanings for the word "Duplex" as applied to cartridges.

Two different powders loaded, un mixed.

Two fronts of ignition..as in Keith's and some military.

Two projectiles, some military smallarms and ?

All three have been around for 80 years and more.

Back to the 45/70 question. Bullet neck tension may be very low or need to go to faster powder. Bullet may be grossly undersized for that particular gun's bore.

Sam

[griz]

With two powders, ie. WC852 (slow lot) and PSA you can load everything from a big belted magnum with a heavy bullet to a 223 with a light bullet. And the powder will be correct for every combination.

This sounds bizarre to me. If you follow that logic, you could mix in a dab of Red Dot and include shotguns and revolvers in your reloading inventory. What am I missing?

[Charmedlyfe]

KP95DAO,

I'm glad you still have all your body parts. Read the manuals (ALL OF THEM). Mixing two or more different powders is strongly discouraged. Why? Because loads tend to settle, which means they are NO LONGER mixed. This defeats the purpose of handloading in that you are creating inconsistency. If you happen to have a strain guage, hook it up. When you fire 50 rounds of your 'blend', you will notice quite a difference in pressure from round to round.

More than a few KBs have been traced to such 'seasoned' loads. When the big companies 'blend', they mix two or more lots of the SAME powder.....not different powders. READ.

[BigG]

I have fired many (over 20,000) rounds using blended powders. I started out using 4831 with a booster charge of Red Dot in a 44 mag. It worked. After much experimentation I gave up using "duplex"(that is two powders loaded seperately) loads in favor of blending to meet my burning rate requirements.

With this you can taylor your loads to your components and your gun and achieve this at much less cost. With two powders, ie. WC852 (slow lot) and PSA you can load everything from a big belted magnum with a heavy bullet to a 223 with a light bullet. And the powder will be correct for every combination.

Don't try this at home!

[Fatelvis]

With the vast array of powers, with varied speeds/densities, why would you want to go and mess ,with mixing them? Just tell me what caliber you`re loading for, and I can give you a dozen powders that would work just fine, even great! Please, if you want to try something as dangerous as this, dont write about it , and encourage other reloaders, (some maybe not as experienced as you) to do the same. We as gunowners/reloaders, dont need any MORE people getting hurt, or dying because of "THOSE EVIL GUNS" After all, if too many reloaders get hurt, or die, how long before a law is passed, prohibiting reloading, to "protect" us?

[KP95DAO]

Lions and tigers and bears, OH MY!

The world used to be flat.

Man was never meant to go faster than a horse could run.

The moon? Are you crazy?

Faster than the speed of sound, unbelieveable.

Ships that go under the water and stay there for months?
Sure you're right.

Sometimes I wonder how we advanced at all. Oh, that's right, there were people out there who were not afraid of the unknown.

Faint not, oh ye of little faith, I shall be gentle. Soon.

[DAVID NANCARROW]

....and I have more extensive testing equipment and knowledge than the powder companies. Well, I don't, but will pray for you.

[DAVID NANCARROW]

It's certainly your right to do with as you please, and will defend it to the end, but I do question as to whether I would advocate it to those you don't know-they may not possess your knowledge or your safety habits. Nice to know it can be done if it ever came down to having no choice.

[Charmedlyfe]

KP95DAO,

In my eyes, you have just lost all credibility. Hey, why not bust up that stupid belief in gravity? Jump off a building, flap your arms, and FLY!!! Same logic applies. Did it ever occur to you that you have just been very lucky so far?

[Mike Irwin]

And why is it that the people who pull this sort of stuff are usually the first ones to start screaming about product defects and suing the manufacturer when something goes wrong?

The people who advanced this stuff had a few things that aren't being shown here:

1. A healthy respect for the possible danger in what they were doing and the dangers that it can pose to someone else who tries it, i.e., not sharing this sort of "information" willy nilly with anyone and everyone.

I've known a couple of serious duplexers who have spent years working up their loads, and they have one thing in common, they won't share the information with anyone who isn't a SERIOUS long-term reloader, someone who is thoroughly conversant in the dangers that can be involved.

2. A willingness to accept the possible consequences -- damaged guns, and even possible injury -- that comes with knowing exactly what they're doing. A newbie doesn't have that knowledge or ability.

3. An extreme amount of knowledge about the products at hand. The earlier statements about powder companies "blending" different kinds of powder lets me know that that knowldge is lacking. Powder companies DO NOT blend different types of powder.

Posting information of this kind in an open forum is not only irresponsible, it could also be dangerous to someone who might try it, and use different components.

The one thing that is always true about duplexing is that it can be VERY unpredictable.

I'm recommending to the moderator that the specicifics listed in this thread involving powders be deleted as a potential safety and liability hazard.

[C.R.Sam]

Seconded.

S