priming charges placement?

[bushka]

Has anyone tried placing the smokeless charge on top of the BP,and what were the results?
The old NRA reloding manual stated sometimes it was mixed with the BP with similar results as against the flashole.
I would surmise putting 5g of 4759 under the bullet would still keep BP fouling down yet mitigate any high pressure spike in the breech.

what say you??

B

[floodgate]

bushka:

The early smokeless powders (around 1890 - 1900) were hard to ignite with the mild mercuric primers then in use, so many reloaders used a "pinch" of Black Powder as a "priming charge" under the main smokeless charge. No real need to do this with any of the primers in use today. And I see no real point in a small charge of smokeless over a main charge of BP. A light smokeless priming charge UNDER the main BP charge IS said to help with fouling, though I have not tried it myself.

floodgate

[Baron von Trollwhack]

I frequently duplex smokeless under black powder in a variety of cartridges to include .45-60, .45-70, .50-90, and 43 Mauser. I always use 4.1 grains of RE-7 right next to the primer now as it dips conveniently with a Lee dipper, although I have used heavier charges. I chronoed some .45-70 loads a long time age and came to the belief that I could figure each grain of smokeless was equivalent too three grains of black in the load. I also figured this was approximate and likely varied by about a hundred speculative factors per load. I often got very little velocity variation with carefully prepared loads. I KNOW black powder barrel and case fouling is reduced by duplexing as I have done for sure. Even the cloud of smoke from discharge is reduced and appears thinner and less in volume. I think the black is burning "better". In a pretty strong gun like a B-78 I tried WW-296, IMR 4198, 2400 and others as duplexing agents but never saw anything I could figure was a different pressure sign attributable to the smokeless, but the s to b ratios were always very small. I have never heard of placing the smokeless on top of the black. Just the theory of that seems a bit silly to me, but there is certainly room for others to inquire into it. BvT

[Ernest]

kind of backwards but Westley Richards used to mix black powder with shredded cordite in their 12 explora loads. By doing that they were able to get a 730 bullet up to 1250 fps and still stay with in proof pressures for a shot gun.