Powder equivalents?

[OB OBrien]

Hello; Need some guidance here please. I have an assortment of powders and would like to know what the equivalents are. For instance how may grains of fffg equal how many grains of Pyrodex RS ? For my ROA pistol how many grains of fffg equal 30 grains of Pyrodex P ? Thanks for the help.
OB

 

[ohio ramrod]

Pydrodex is made to be equivalant to black powder by VOLUME not weight.I suppose some one who shoots pydrodex could give you the equivalant grains but the only people I know who use it just use volume for volume. It is a sad fact that in some areas you just cann't get black powder unless you buy large quanities and have it shipped in. The HASMAT free is the same for one pound or one case.

 

[mykeal]

Here's a chart I picked up a couple of years ago. I have lost the reference as to who the author is and where I got it, so apologies to that gentleman; it obviously took a lot of work to create this data. I believe it was on this forum but I'm not at all sure.

Anyway, I hope it's clear enough to read. One caveat: black powder volume measures are not terribly well calibrated to any standard that I know of. Since grains is really a weight metric you won't find any standards for 'grains by volume', and that leads to bp measures which tend to vary considerably from brand to brand. The person who made this chart left no reference as to what measuring device he used, so I'd be a little cautious about the exact weight values he obtained. However, since he (presumably) used the same device each time the brand-to-brand comparisons should be valid, and that's what you are after.

 

[MSW]

your question is a valid one, but you should remember that (in one guy's opinion, anyway) the fun part of this addiction is that each gun has its own quirks, and that the whole process or working up the best load for an individual piece is that the process is essentially experiental and not theoretical, so i'd work up the most satisfactory load for your particular gun and not get too terribly worried (except, perhaps, as a mental exercise) about the interchangeability of pyro to 3F.

just one guys thoughts, and might well be worth what you paid for them

 

[OB OBrien]

Thanks gentlemen. The chart gives me something to study. The advice is great. I'll just go out to the range and see what the equivalents actually are.
Thanks again
OB

 

[Zonie]

Using the Lyman Black Powder Handbook and its tables for a .45 caliber Ruger Old Army revolver I can give some of their velocity results between GOEX 3Fg and Pyrodex P. (powder represents a volumetric measurement, not an actual weight measurement. .457 lead roundball, Rem #10 caps):

25.0 grains
GOEX = 697
Pyro P = 703

27.5 grains
GOEX = 762
Pyro P = 744

30.0 grains
GOEX = 842
Pyro P = 786

32.5 grains
GOEX = 879
Pyro P = 890

35.0 grains
GOEX = 924
Pyro P = 924

37.5 grains
GOEX = 992
Pyro P = 1002

40.0 grains
GOEX = 1076
Pyro P = 1098

I believe the reason for no listing of Pyrodex RS is because generally speaking it is a 2Fg equivalent powder made for Rifles and Shotguns.