Anybody making a duplex powder measure?

Want to use a blackpowder duplex charge in one of my rifles.  Lyman, well Ideal, made a series of powder measures that threw a small smokeless powder charge ahead of a large blackpowder charge.  But those are probably a century old if you could find one.  Anybody making anything like this today?

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Here is a No.6 and IMO a good price.

Pete Allen used to make an investment cast, full adjustable, duplex powder measure. They are often carried by various dealers at The National Muzzleloading Rifle Ass'n National Matches.

I made my own out of components from a MEC reloader. It works just fine. It uses custom bushings (I just had a friend turn a bunch of "bushing blanks" and then I finished them on my drill press). Once you work up a load using an adjustable measure, you just settle on a load and then fabricate the bushings needed. Really not all that difficult. Costs are minimal.

I used it for years in my 40/65 until the local matches went NRA knockdown (NRA Silhouettes require straight black).

Frankly, after using both duplex and straight black over the years, I much prefer duplex loads. No blow tubing and can shoot all day without fouling problems. Clean up is easy with both.

Dale53

Boats;
There is absolutely NOTHING wrong with throwing the two powders from two different measures. It is just one more thing that you have to watch out for. The duplex measures take away the possibility of only dropping one charge.

However, I did it JUST that way for a pretty long stretch without problems.

4759 is a good choice except that it doesn't measure all that well in most measures. 4227 is often used without problems and does measure well. My choice is RL-7 as it measures well and is a bit slower than 4227.

Duplex loads have worked extremely well for me. There is no worry about ringing a chamber, and you can shoot all day long while using black powder without using a *&^%&** blow tube. There are NO fouling problems. I stayed with 10% smokeless as I didn't need to increase the power over black. It does increase the velocity a bit and is about equal to increasing the black powder charge three grains for each grain of smokeless. 

For instance, black powder only charge of 65 grains. Loading 10% smokeless (6.5 grains) with 58.5 grains of black powder will give you the ballistic equivalent of 79.0 grains of black powder. I would first establish a load and compression ratio with straight black powder. Then I would use the same compression with a duplex load. This compression keeps the powders from mixing. Most of my duplex loads were done with Goex with compression going to as much as .350" (I dropped the black straight out of the measure as I found I got the same results with the compression die as I got with the extra trouble of using a long drop tube and then compressing).

As the Froggie says, "YMMV"

Dale53

Boats;
Just so it is clear, the smokeless powder goes against the primer with the black on the top. I also used a .060" LDPE wad against the bullet base. 

Lyman's Cast Bullet Handbook has duplex loads on the 45/70 complete with pressure data. It's a real eye opener. Look in the Ruger #1 &#3 section.

Dale53