Have any of you got into Duplex or triplex loading ? Results ?
roger

Sure; I routinely load ten percent 5744 under Goex Cartridge Black Powder.
Smokeless duplex? NO. You are treading on snakes.

IIRC when Dick Casull originally developed the 454 he supposedly used duplex and even triplex loads. This was in gun mag articles way back when and is worth what you paid for it...

yes 80's South Africa Denel ( Somchem ) powders
We had few options with big gaps between burn rate options
On advice from the chief ballistician at Somchem we loaded propellants of two differing burn rates at percentages advised to achieve desired velocities. The cartridges in question various 458 cal customs made from necked down 404's and 416's of varying length. Our friend late Dr Mauritz Coetzee who was a huge proponent of this published his results with the 458 Short Majoor in Man Magnum magazine

The Short Majoor on the left



This cartridge the only one I ever saw show pressure signs when shot in the Lowveld and not when shot on the highveld

If one would thoroughly mix the powders together one would just be creating a different powder.

Proper load up work would need to be done.

If layering them I would not be sure what would happen and not recommend it.

I see no reason if you live in a place where many types of powder are available.

We actually tried to experiment, but I think we were not adventurous enough.

But, with our 700 Nitro Express loads, we were getting hangfire, until we started putting a few grains of Bullseye under the powder charge, which cleared the hangfire and everything worked great.

Elmer Keith writes at length in Hell I Was There. It is worth buying to read about that.

In essence he thinks that the US Ordnance Department were putting out fake news (yes..even then) about duplex loadings to mask the fact that they were actually using primer tubes (like on an artillery piece) to ignite the powder from the front end. To explain that's a long metal tube, or pipe, that fits over the flash hole, inside the case, so that the primer flame goes directly to ignite the front part of the charge. So therefore the charge burns back, away from the bullet or shell. The result is velocity for lesser pressure.

Or at least that's as I recall. I have neither read no seen Hell I Was There for some thirty years.

quote:

Originally posted by p dog shooter:
If one would thoroughly mix the powders together one would just be creating a different powder.

Proper load up work would need to be done.

If layering them I would not be sure what would happen and not recommend it.

I see no reason if you live in a place where many types of powder are available.

I did it in the early 70s with the 375 and mixing 4064 and 4350 to get a burn rate between 4064 and 4350.

I mixed the powders 50/50

Nothing special about it. A lot of people think the flame propagates through the powder like it does with the petrol/air mixture. However, the burn rate is each granule. Ideal ignition would be for every granule of powder to ignite at exactly the same time.

played with it many years ago because Elmer said so, what a crock, and a waste of time. No need with todays powders as far as Im concerned, even back in Elmers day it was just more of his BS IMO, but to each his own..and I consider it dangerous more or less.

quote:

Originally posted by Atkinson:
played with it many years ago because Elmer said so, what a crock, and a waste of time. No need with todays powders as far as Im concerned, even back in Elmers day it was just more of his BS IMO, but to each his own..and I consider it dangerous more or less.

Ray,

A normal load is already mixing powders because the granule sizes of any powder are not exactly the same size.

I had ignition problems with my .577 BPE using 4198. The primer would fire, driving bullet, wads and powder about 6" into the bore. 2 grains of Unique next to the primer solved the problem.

Dave

While it is true that powders contain a variety of sizes, those sizes are controlled by the powder maker, mixed and tested in controlled conditions to produce a burn rate/pressure specific to a powder's number and in batches that are pretty uniform throughout AND tested/adjusted from batch to batch for uniformity...NOT quite what mucking around with mixing in your back yard to make some kind of witches brew you may THINK is something equal to some "middle" number...all that garbage is just in someones mind and REALLY dangerous because I really DON'T think anyone outside a laboratory has the specialized equipment OR the expertise to actually know all they DON'T know about what they are doing.

It sounds really cool though...to the non-Illuminati.

Dam...these AR forums can be a dangerous place for beginners.

Good Hunting

Because it will have an average size and that average will give the desired burn rate.

Mix 4064 and 4350 at 50/50 and you get the in between burn rate.

What I do know is it works

See Alf's post above on African powders etc.

Like a solid fuel rocket, the whole grain is ignited at once. The shape controls the burn rate. For example, the Shuttle SRBs grain is designed so the surface area decreases as it burns which reduces the thrust as it ascends. As a side note the Shuttle's two SRBs and three main engines had about the same thrust as the Saturn V at launch. However, the thrust reduced as Shuttle climbed and drops way of at 2 minutes when the SRBs separate. Actually before separation the thrust of the SRBs is very low.

quote:

...No need with todays powders as far as Im concerned, even back in Elmers day it was just more of his BS IMO, but to each his own..and I consider it dangerous more or less.

I agree with Ray, old Elmer was full of BS in many ways. Not all of course, he did have lots of cred, but he certainly did promote “questionable” practices.

Dick Casull used triplex loads because he didn’t have powders like H-110 or Lil’Gun. Today there is absolutely no reason to “blend” or mix powders in any case to give better performance. This excludes using a small “priming charge” in a few very large cases.

.

Love it when folks call ideas BS

Interesting little detail though that many of the big name "guns and reloading experimenters"were at some point in time employees of the military establishment and many of the contributors to the very early editions of American Rifleman and or reloading manuals and annuals were in fact professional ballisticians.

In the history of gun propulsion we see a general quest for higher velocities within the pressure and temperature limitations of the system.

Duplex loads or more specifically staged loads are nothing new however it is not a simple as loading a round with two layers of granular propellant.

The idea is that the first propels the second down the bore where it ignites; the second then being becomes a travelling charge.

Other forms of novel staged propulsion system would be lining the barrel with a propellant liner .

The latest sags on this theme is work done on modern caseless ammo. The propellant is encased in a combustable tube where both propellant and tube burns to give propulsion.

duplexing is not mixing powders.
it is using a fast powder to help with a more consistent ignition of a slower powder.
usually a powder too slow for the case size.

why?
well cause it has benefits most don't understand.
one benefit is for high speed cast bullet shooting

quote:

Originally posted by Lamar:
duplexing is not mixing powders.
it is using a fast powder to help with a more consistent ignition of a slower powder.
usually a powder too slow for the case size.

why?
well cause it has benefits most don't understand.
one benefit is for high speed cast bullet shooting

I have the exact opposite view to you as to what is a duplex load.

However, the usual meaning of the term indicates that a small charge of fast burning powder is used to ignite a larger charge of slower burning.
Not mixing powders; that is called "Blending"; that is how they get lots of powder to burn at "canister" rates. But not from mixing differing powders.
You are blending. Probably safer than some duplexing done in the past. What Saeed does is very safe.
I managed 105mm Tank Ammunition for AMCCOM, and I got involved in all of this, (watching, not actually doing it), from propellant blending, primer manufacture, which is like a one pound charge in itself (like a duplex load), projectile manufacture, and loading, etc.

I expect there was a time when some did it out of a real necessity. But with the powder variations available today it sounds an answer looking for a problem to me, in all the wrong places.

quote:

Originally posted by Mike McGuire:
I have the exact opposite view to you as to what is a duplex load.

Then you would be wrong.
Duplex,and triplex loads are stacked to help ignite the one on top, and is mostly used with large capacity calibers.
With todays powder, its not used as much.
Think of it like this.
The bullseye sits at the bottom as ignition, the middle powder is then fired,and both are used to ignite the large load on top.
Otherwise it is just a mix of powders, and would not work in stages,and would probably result in booms.

If you look at Saeeds example, the fast burning powder must be at the flashhole, otherwise it would not work.If it was mixed, it would not work to ignite the slower burning powder.
That is why it is always used in a compressed state, so the powders cannot mix easily.

quote:

Originally posted by LeeC:

quote:

Originally posted by Mike McGuire:
I have the exact opposite view to you as to what is a duplex load.

Then you would be wrong.
Duplex,and triplex loads are stacked to help ignite the one on top, and is mostly used with large capacity calibers.
With todays powder, its not used as much.
Think of it like this.
The bullseye sits at the bottom as ignition, the middle powder is then fired,and both are used to ignite the large load on top.
Otherwise it is just a mix of powders, and would not work in stages,and would probably result in booms.

If you look at Saeeds example, the fast burning powder must be at the flashhole, otherwise it would not work.If it was mixed, it would not work to ignite the slower burning powder.
That is why it is always used in a compressed state, so the powders cannot mix easily.

Just out of curiosity I asked some shooters and got mixed answers. Also mixed on the Internet unless Black Powder forums. I think it is also spit on this thread.

However, thinking about it and housing in Australia "a duplex" is like two separate houses joined and which for fit your definition of duplex loads.

So if we accept Duplex loads to mean layered powders why would we call loads where powders like 4064 and 4350 are mixed I think Alf's answer for Sth Africa was about mixing powders. So what do we call mixing powders.

As a side note, with pipe smoking different tobaccos are often mixed but then someone will say instead of mixing the tobacco they will layer the tobacco.

Actually, it probably does not matter because as this thread shows start a topic on Duplex loads and you will get answers covering both sides.

Duplex= 2 powders stacked
Triplex= 3 powders stacked
Blend= 2-3 powders mixed

Duplex loads are layered loads. Pure and simple.

I gave you the correct, official Army Ammunition, and Industry terms;
Mixing powders is BLENDING.
Layering them is DUPLEXing, etc.
No confusion in the correct terminology.
If one gets mixed answers, then half of them are wrong.

55gr. psp win 680/5020 13/25 win " " 10 shot 3/4 " group all powder burned

52 hpbt speer 680/5020 14/26 " " 12/10/02 Destroyed Rifle!! NO MORE DUPLEX LOADS.

Had been duplexing for many years. It finally caught up to me.
A fella once asked me " If you finally get all that powder to burn ,How can you tell beforehand you don't have too much? I think I learned the answer.

braised the head of the cartridge to the face of the cracked bolt. I got a little gas in my face and that was all. I was a little shaky as I put the rifle down'
I put a new bolt in but experienced hard,hard lift even with super mild loads. The Mod. 98 action had severe set back .
I lost a rifle but no blood.
roger

"Blending" that is it.

Duplex and Blending.

I have done Blending but have never done Duplex'

What about propellants where the granule itself is a layered wafer of propellants of varying chemical composition and burn rate What is this ? blended or duplex

quote:

Originally posted by ALF:
What about propellants where the granule itself is a layered wafer of propellants of varying chemical composition and burn rate What is this ? blended or duplex

Now that I am better informed I would say Duplex.

However, I have done both with 50/50 4064/4350 in the 375. Mixing both or puttin one in first and the the second made no difference.

Perhaps for general use Duplex could be classed as a load where an easy to ignite fast powder is an aid to the primer.

quote:

Originally posted by ALF:
What about propellants where the granule itself is a layered wafer of propellants of varying chemical composition and burn rate What is this ? blended or duplex

It's an entirely different category, known as transgranuled.

duplexing is used to increase pressure or to extend the primers flash either longer in time or deeper into the slower powders column.

you have to be very careful about doingthe duplexing and the powders your using.
you can spike above the rifles ability to hold pressure with just the initiator powder.

you don't just keep on adding red-dot, you have to work to a slower initiator powder if you need more just like working up a load.

you can push a 55gr jacketed bullet just over 2-K fps with 4grs of red-dot in the 223 case, what do you think is gonna happen when you put another powder that works just fine on it's own on top of that?

you don't just go duplexing a powder that don't need it and keep adding more of the higher pressure spiking powder.
what happens is you end up treating everything above the faster powder like it is bullet weight and end up with a too fast powder under a too heavy weight [or as we called them down on the west side of town,,, a pipe bomb]

MIke,
The only duplex loading I tried was tha of Elmer Keith, loading a tad of Bullseye or Unique under and over a load of slow burning powder, the effect was supposed to be the hot primer effect of the day..He later ran a tube out into the powder charge to shoot the hot powder down the tube to get better ignition..Didn't work..It was a scary process IMO or rather on my part, so I played elsewhere. With today powders and primers its an exercise in futility and apt to blow one digets off!! oe worse IMO..I decided the learning process itself was not for me..

it's not a lesson in futility it is just a way to control and manipulate pressure to attain certain goals.
it's similar to changing a powders burn rate with a shoulder shape or by jamming a bullet into the rifling.

if you can't answer simple questions like why the243 works with 4350 and slower powders but the 308 doesn't do well with them.
then you shouldn't be playing with any other advanced reloading techniques either.

Read "Hell I was there" by Keith and you will discover that Keith's "Duplex load" is a simple brass tube to extend the primer flame to the base of the bullet, no powder in the tube or using multiple powders. It is exactly the same as the standard primer arrangement for artillery shells, just on a much smaller scale. Keith did experiments prior to WWII with his 333 OKH wildcat, and while an inspector at the Ogden armory during WWII did govt sanctioned experiments with the 50 BMG cartridge. The process works, you do get a velocity increase of 150-300 fps due to better powder burn - but it's expensive as it requires careful machining to fit the tube in the case and it makes reloading more difficult. If you read his Gun Digest columns collected in the "Gun Notes" volumes 1 & 2 several times he speaks AGAINST trying to use multiple powders in a single load as Dick Casull tried.

When loading .500 S&W with 400 gr Woodleigh bullet, I tried Hodgdon H110 and VV N110. Both powders with very similar burning rate, but different density and type (ball powder vs extruded).

What I found is that H110 is a little bit too much dense for it and N110 is a little bit too fluffy. But I never was "brave enough" to try to mix it.

Max load for H110 is 44 grain - call that X
Max load for N110 is 39 grain - call that Y

So simple equation:

(X/44)+(Y/39)=1
39X+44Y=1716
Y=(1716-39X)/44

So there could be mixes like that (max loads):

5 of H110 + 34,57 N110
10 of H110 + 30.1 N110
20 of H110 + 21.27 N110
30 of H110 + 12.4 N110
40 of H110 + 3.55 N110

What do you think? I know that it is not that simple . . .


Jiri

Jiri.
no.

you'd basically end up just speeding up the H-110.

quote:

Originally posted by Lamar:
Jiri.
no.

you'd basically end up just speeding up the H-110.

Yes, this is what I need, speed up H110 a little bit.

Or I need slow down and/or make N110 a little bit denser. I believe that fine tuning mixture could yield in better efficiency and better muzzle velocity with less powder.

You can't put more than 39 gr of N110 in (it is compressed load). It yield 1558 fps. Cases easy to extract.

43 gr of H110 yield 1535, 43.5 1617 and 44 1644 fps. Recoil and blast is huge. Cases easy to extract.

Maybe I can ask national proof house to test loads in test barrel.

Jiri

quote:

Originally posted by bartsche:
Have any of you got into Duplex or triplex loading ? Results ?
roger

There were two articles on Duplex loading for the OKH Cartridges. The first was vague due to the war. The second had more information. They used flash tubes and single powder, two powders and then three powders.
Rocky Gibbs and others used flash tubes to so there is not uch new there.

I don't post much so hard to figure adding attachments.