Duplexing Powder

[rodmkr]

From the start I do not do it but having read about want to ask a question,
Do you simply mix the powders together?
If not how do you keep them from mixing in the case during transit
to the range?
Would it not be simpler to just use magnum primers?

Have a large amount of WC860 I want to use.
Have used it as a stand alone powder but do not get the velocities I wanted.
Used it in 7X57 MM ,8X57 MM and 30/06.
That is the reason for doing all of the reading about duplexing.

 

[BBerguson]

The only loads I’ve ever shot that were “duplex” was when I wanted to use up some Pyrodex and save my limited supply of black powder in my flintlocks. I start with a small charge of bp and finish with the Pyrodex. Walmart was “giving” the sfuff away many years ago so I bought the last two cans they had. I think it was like 4 bucks a can or something.

I’ve read about guys successfully loading duplex loads with smokeless but I’d never do it myself, don’t have the need or the confidence. Edit: And for what it’s worth, if I get a load that shoots well, I don’t worry about the velocity.

 

[S Mac]

I have never tried it myself, but my understanding is that you don't premix, end up with a full case, that in my mind would keep in "layers".

 

[Kevin Stenberg]

+1 for Mack. The total amount of powder should be compressed from bullet seating. The compression keeps the 2 powders from mixing.
Drop the faster burn rate powder, without disturbing the first powder drop the second slower burn rate powder on top of the faster powder.

 

[Bisley]

The only time I read of a successful duplexing load was in Barnes Cartridges of the World, during the 1970s. The duplexing was done by Casull (sp?) in .45 Colt cases to develop his 454 loads. Even at age nine, and without handling any guns, it seemed complicated and prone to danger. But, the .454 is successful and has a following.

 

[Rick]

Dick Casull used triplex loads in developing the 454. Dick Casull was both smarter and braver than me. I would never attempt it, far too much to know that I don't know.

 

[Ian]

I've done it and had really good results using WCC 872 and Blue Dot, though I've since learned that IMR 4198 makes a much better kicker charge. All you're doing is boosting the primer's intensity and duration and getting the heat and pressure initiated so the main charge burns as it was intended to in, say, the 20mm Vulcan cartridge. As was said DON'T mix the powders and maintain compression to prevent mixing of booster and main charge during handling. Done right you can make 872 burn like 4831 and 867 burn like 4350.

 

[RicinYakima]

You are now working in the "art" of reloading, not the "science" of reloading. I have used SR4759 under black powder, and black 4F under surplus 4831. For me, it was more trouble than it was worth.

 

[fiver]

meh, the military has been doing it for about 90 years, and the BPSA actually has rules on the amount of kicker you can use in a black powder charge.

 

[Rick]

meh, the military has been doing it for about 90 years, and the BPSA actually has rules on the amount of kicker you can use in a black powder charge.

Re-read the OP and I'm pretty sure he's not talking about military shells or black powder.

 

[fiver]

I know what he is talking about.
i'm just pointing out that they ain't all that far out there,, rather than writing a 6 paragraph explanation on how they work and what powders to look for.

 

[Walks]

My Dad used to do it 60yrs ago in an OLD Sharps, I don't remember the cartridge, but it was longer then his Middle finger and almost as "fat" . My middle finger is 1/2" longer then his. So I'm thinking .50-110, used a small charge of Bullseye over ?? BP ??.
One shot seated over the crosssticks, created at least 3X the BP smoke then his old .36 Navy Colt. The barrel seemed longer then our '55 Chevy Nomad and probably as Heavy. But He could hit an old MJB 1lb coffee can 4 out 5 times starting at 100 paces.
He said the "starter" charge made all the difference.
i was never brave enough to try it in my italian repro in .45-70. Besides I don't think it would've helped.

 

[Bret4207]

A lot of people have done duplex loadings. In every case I've read of (never done it myself) the goal was to use a case full of powder so they couldn't mix. I can see the idea behind it, but I've never had to resort to it. The most recent guys I knew of doing that were not guys that I'd willingly follow into that type of experiment, but they thought they were geniuses. Both lived, so maybe I'm wrong.

 

[John]

I have duplexed 872 and 860. I use a fast RIFLE powder and somewhere between 3-5 grains. What you are after is a clean burn. Start out with the 860 loads by themselves and get a fix on the unburned powder. Add your kicker charge and eyeball the unburned flakes. You want a full case or as mentioned a slight compression. I did not want a clean barrel as that might be approaching more pressure than I wanted the old 98 to see, I wanted a large reduction in unburned powder but a few flakes left.
Why leave some? I also bought a bunch of 7383 and have a large respect for what happens when you get all that stuff burned.

 

[CWLONGSHOT]

Always scared the bejebus outta me. Nope not this guy... Im good.

CW

 

[Cliff]

Nothing to it really. I made these loads back in 2014.
Copy and pasted from another site.........

Chronographed a few more loads of 50.0g. WC860 with a booster charge of 4.0g. N100 in different rifles.
Starline nickel plated brass / CCI 200 / RCBS 45/405/fn

The results from the 18'' Guide gun (post #33) were

Temp. 71 degrees / ten feet from the muzzle.

1 - 1347 fps.
2 - 1339 "
3 - 1350 "
4 - 1349 "
5 - 1360 "

Today the temp. was 30 degrees, measured 10' from the muzzle.

Marlin 1895 22'' barrel

1 - 1431 fps.
2 - 1401 "
3 - 1417 "
4 - 1411 "
5 - 1412 "

Marlin 1895 26'' Cowboy

1 - 1427 fps.
2 - 1423 "
3 - 1402 "
4 - 1379 "
5 - 1403 "

Buffalo Classic 32'' barrel

1 - 1432 fps.
2 - 1417 "
3 - 1424 "
4 - 1430 "
5 - 1424 "

Tried 45.0g. of IMR5010 with 4.0g. of N100, Starline nickel plated brass / CCI 200 / RCBS 45/405/fn. Used a single layer of tissue paper over the booster charge, cut to size with the sharpened mouth of a 45-70 case.
Marlin 1895 22''barrel, measured ten feet from the muzzle.

1 - 1309 fps
2 - 1311 ''
3 - 1331 ''
4 - 1316 ''
5 - 1316 ''

No un-burnt powder left in the barrel.

 

[Joshua]

None of this is gonna be of much help to the OP. But, I want to chime in. These powders are interesting to me.

If I had a 25-06, 7mm rem mag, 300 win Mag, or similar over-bore. I would be all over these WC872, WC867, WC860 type powders. I’d buy a pallet.

Or, if I was given/stumbled across some locally, I would use it straight and compressed (no duplex) in 30-06 with heavy bullets. I currently do something similar with H-414 in the little 30-30 and have been very happy with the results.

I’ve read quite a bit about duplex loads with these types of powders. I’ve even considered buying 6 jugs of this stuff to try it out.

I’m probably gonna create some controversy with this next statement. Of the two most common “unsanctioned” reloading activities, I think that reloading using filler is much more dangerous than reloads using duplexed 20mm cannon powder.

Josh

 

[USSR]

Uh, ain't going there.

Don

 

[Cliff]

I still have the four 45-70's. All in one piece. It's good info to know in times when there is shortages on powders. And fifty cal./20m.m. powder I have plenty of.

 

[Cliff]

The powders that I tried were...

50g. WC860 with 4g. AA Nitro 100

45g. IMR 5010 with 4g. Nitro 100

50g. IMR 5010 with 3g. Nitro 100

50g. US869 with 4g. Nitro 100

50g. WC868 with 4g. Nitro 100

Powders that I have but didn't try were H50bmg, WC872 or V.V.20n29.