beginner's duplexing questions (45-70)

[doubs43]

In post #15, 4th paragraph, I state that my loads are slightly compressed. However, it's still a good idea to emphasize that smokeless duplex loads NEED to be compressed for best performance. As Turbo1889 comments, a compressed duplex load is likely to give more consistent ballistics than an uncompressed single powder load. My 45-70 loads give 10 fps average deviation.

In my experience, no matter the boolit weight, you can't possibly stuff enough WC-860 in a 45-70 or 38-55 case to generate excessive pressures. The only way you'll get high pressures is by using too much ignition powder. I find that 3.0 grains in a 45-70 & 40-65 or 2.5 grains in a 38-55 is enough to do the job. The only danger is a double charge of the fast powder. I'm very careful and double check to make sure I don't do that.

[mattbowen]

Okay;
I have a question I see everyone talking about WC-860. What is the difference between WC-860 and WC-872 and can WC-872 be used in place of WC-860?

Also I see that widener's also has WC-867, From the number I would think that this would be closer to WC-860 so would the loads be close enough to use?

Thanks

Matt

[Char-Gar]

Some years back when WC872 was really cheap, many of us played with it. It was developed for the 20mm Vulcan round.

In most applications for bottleneck cases it will burn OK with light compression. It produces outstanding accuracy in the 30-06 and like medium capacity rounds with cast bullets. You can't get enough power in the case to get you into troubles.

When it comes to straight cases like the 45-70 that is another matter. To get a decent burn it will require a kicker charge of medium powder like 3031 or something in that range. Stay away from ball powders that can mix with the slower ball powders.

Many of us have done it with no problems and good results. BUT we are dealing with the unknown here. There is only anecdotal data, none of which has been lab tested. Therefore I am very hinky about sending someone down that path.

I certainly would not shoot such loads in a Trapdoor Springfield or any other weak action. I don't think the pressure of such loads would be excessive, but nobody knows for certain, therefore best not to do it.

We have added many, many new members to this board since the days we freely exchanged data and out of the box experiences, and too many of those new members don't have good sense. l

[mattbowen]

Chargar;

Thanks I understand, what do you think about the WC-867?

[Longwood]

I am new to 45-70 shooting and am doing a lot of testing with different powders, different boolits - lubed and two different types of paper patched made from my homemade molds- and bullet metal formulas.
Can a powder as slow as 860 be cut back some?
I was told on another site that I can fill it to capacity or, as low as, 70%.
I know powders like 4227 can burn very erratically if you try that.
If I were to try it with 860 and 405 gr to 535 gr boolits, should I use a thin card wad over the powder and or filler and another card wad?
I am old and retired and only plink nowdays so I want to keep the price down so I can do it very often.

[redneckdan]

I have done so. On method is to seat the bullet deeper if possible. Another is to fill the space with something. I prefer cream of wheat. More biodegradable then card wads. One load I used was the lee 350gr bullet with 3.0gr of red dot and 35.0gr of WC860. Can't recall velocity off hand but it was much friendlier than the full snort loading. I have done the same thing with my .30-284 with similar results. Haven't tried it yet with my 375 H&H.

[Char-Gar]

mattbowen.. I have no experience with the powder you mentioned, so I don't have an opinion. Back when WC872 was so cheap, I bought 64 pounds of it and still have a bunch. Enough to last me for quite a while.

redneckdan... If there is still some space after I have put in the proper charge of WC872, I top it off with Precision Shotshell Buffer to get light compression. I am hinky about using natural fillers like cream of wheat, which have been known to take on moisture from the air. When that happens it can swell and push the bullet forward or turn into a hard plug. If you have a hard plug in a bottle neck case, that can cause a real pressure spike. These are the reasons I go with an inert non-organic substance like PSB.

The use of card wads can cause real problems if someone inadvertently leaves an air space between the wad and the bullet. The wad acts like a piston and compressing the air space and barrels can be bulged or worse.

[wiljen]

I've used the 1/2 inch vegetable wads in the 45-70 to reduce case capacity when using powders that dont like air space.

[Cap'n Morgan]

What kind of ES and DS variation are you guys getting with duplex loads?

[mattbowen]

Chargar;
Thanks for the reply. Is WC-872 as good as WC-860, I have read that some people have had problems with pressure spike in hot weather. I live in SC were it is all most always hot.

Thanks again

Matt

[Jim]

Matt, when I lived on James Island, I had a place to shoot down highway 17, just south of Ravenel. I know all about that heat and humidity.
One summer, I had been working on a new load and was getting some high pressure signs that should not have showed up. It was one of those 95* low country days. Come to find out, the ammo was getting hot.
Next trip, I put my ammo in trays and carried them in a cooler with a little ice in the bottom. I left the cooler top open but the ammo stayed in the trays in the bottom. The pressure signs went away and the load worked fine.

[mattbowen]

Jim I had that happen at the house when I was checking the zero on my 3006 last year, so I started shooting in the morning or afternoon.

Matt

[Jim]

There ya' go, Matt. 'Specially if ya' can find a nice shady spot, right?

Them nats and skeeters eatin' ya' up down there yet?

[mattbowen]

I sprayed the yard yesterday evening to kill the unwanted ones

[frnkeore]

I don't know how relevant this data will be to this discussion but, here goes.....

This data is dated Feb of '90 in my chrono book.

The rifle is a 1878 Sharps Borchard, 31" lg Octagon Douglas barrel, 20 twist.

WW cases and F210 primers and a light foam wad against the powder.

Bullet is a NEI 430 gr spitzer cast 20/1.

1. My loads aren't compressed. They take up about 65% of the case capacity.

2. They are not fixed but, breech seated.

Load- 15.0 gr WW296 under 27.5 gr IMR4831
Velocity- 1473
Ex spread- 10 fps
SD- 4 fps
Accuracy for 5 shot group- .60 @ 100 yds

Increasing 2.5 gr 4831 and decreasing by the same wasn't as good.

I'm another advocate of 10 Unique, with that load (all other things the same) and no wad, I got ........

Velocity- 971 fps
Ex Spread- 19
SD- 6.9
5 shot Group- .84 @ 100 yds. 4 in .48

Frank

[grumman581]

A second 45-70 load that has performed well is the 405 grain Lyman plain base boolit with the WC-860 reduced to 56.0 grains.

What kind of velocity are your getting with that particular load?