45-70 Duplex loads

[Old Warrior]

Hi guys, new to the site. Been reloading since early 1970's but new to duplex loads. Any help would sure be appreciated, Thanks

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[dangerranger60]

If you are talking about mixing powders, Don't! Without a Chemistry degree and an Explosive lab at your disposal, you are playing with fire. There are lots of commercial powders out there that will give you all the pressure your gun can handle. and do it with a predictable pressure curve.
What kind of loads are you trying to achieve? DR

 

[Old Warrior]

I am going to use a load that JS Wolf used in his Springfield trapdoor. I have a 140 yr old trapdoor carbine that I am wanting to shoot a load that contains 5gr of 4227 next to primer and 50 gr of 1.5 Swiss BP on top of it.

 

[thorborg]

My opine; clean the gun more often and stick with traditional. But if you must, If not compressed, use Dacron wad to keep it there. watch for pressure signs. (Dacron may add to the increased pressure too!)

 

[Old Warrior]

My opine; clean the gun more often and stick with traditional. But if you must, If not compressed, use Dacron wad to keep it there. watch for pressure signs. (Dacron may add to the increased pressure too!)

Not really concerned with the amount of cleaning, that is just part of shooting a BP. But from what I can read, it adds to the accuracy of the old cartridge by quite a bit.

 

[Nosferatu]

I am wanting to shoot a load that contains 5gr of 4227 next to primer and 50 gr of 1.5 Swiss BP on top of it.

Why?

 

[Old Warrior]

Why?

Lol, I guess that is always the question. But, I collect old guns and shoot old guns and just like to see how accurate they can be.

 

[Quirt Evans]

Duplex loads were used as a way to reduce BP fouling and long range BP shooters have fussed around with duplex loads for many years.
But I'd not be playing around with such loads with those old guns made of soft steel.
If you want to work with some duplex loads you should do your due diligence and research, and get a rifle made with modern steel.
In the end, the BP made today is more consistent, and duplex loads don't have the appeal they once had.

 

[CountryGent]

When I saw the thread title, I thought it was going to be something along the lines of the M198 duplex cartridge.

 

[Nosferatu]

Lol, I guess that is always the question. But, I collect old guns and shoot old guns and just like to see how accurate they can be.

Fair enough. I don't have any experience with duplex loads, so I'm just curious why it's worth the risk.

Common safety protocol for reloading has always been to never mix powders since I got into reloading, so this is new to me.

 

[Old Warrior]

You are absolutely correct about the blackpowder quality today, although it is far more difficult to obtain than previously. Goex went out of business and was bought up and supposed to be produced again, but dealers still can't get it. Swiss is, IMO, better powder but last I bought was only available at Buffalo Arms in Ponderay. And it is a 5 lb minimum order.
But long range guys still like duplex loads and the Government used them to proof test Army revolvers for years. And they blended the smokeless and BP.

 

[Old Warrior]

When I saw the thread title, I thought it was going to be something along the lines of the M198 duplex cartridge.

View attachment 2223731

No, mine are just plain old 45-70 topped with a 405 gr hollow base soft cast bullet.

 

[Old Warrior]

Fair enough. I don't have any experience with duplex loads, so I'm just curious why it's worth the risk.

Common safety protocol for reloading has always been to never mix powders since I got into reloading, so this is new to me.

JS Wolf worked on research for loads on the trapdoor for 30 yrs and wrote a great book with tons of research in it, which I have, but cancer got him in 1991 and a lot of his knowledge went with him. So, I am seeking out guys like him, that have tinkered with duplex also.

 

[DirectDrive]

 

[NeoBlackdog]

Be a shame to blow up a 140 year old gun.

 

[Old Warrior]

Be a shame to blow up a 140 year old gun.

Roger that!!! That is why I am looking for all the info I can find, pro and con.

 

[P7M13]

Do you have a copy of the Lyman BP Manual?

 

[arakboss]

I have done it and lived. I won't discuss it here because it causes too many panties to twist up. I sent you a link in your PM box with source for info on such topic.

 

[Old Warrior]

I have done it and lived. I won't discuss it here because it causes too many panties to twist up. I sent you a link in your PM box with source for info on such topic.

Appreciate the input.

 

[dangerranger60]

So in years past target shooter Harry Pope put a small charge of BP under a mild charge of smokeless powder because BP was so much easier to ignite. he got away with it because it was in a very strong falling block action with a 1 1/4" bull barrel. and because it was a very mild load. this is something not needed today because we have improved the priming to the point it can ignite even the slowest burning magnum powders.