doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com black powder shotgun pressures

Does anybody know where to find them???

Lyman has published a Black Powder Handbook in the past, may have a current edition in print, not sure. Pressures were given for shotgun loads, though primarily for muzzle loading. As black is much less sensitive to external conditions than smokeless I suspect pressures would be similar loaded into a regular hull. It is noted that pressure recorded by DuPont back in the late twenties I believe it was with then current Dupont FFFG black using 3 drams under 1¼oz shot showed a pressure of near 9,000 psi, higher than what Lyman recorded in their testing using "Modern" GOEX powder.

Get the Lyman book....

Pete

It strikes me that those pressures are surprisingly high for black in Drew's first graph (near 10,000 psi!). The powder charges do seem quite heavy in Pete's tables; the graphs seem not to reflect the data in the table - they all look the same to me?

I tend to stay in the 2 1/2 - 3 dram range.
RG

RG - Miller's example used 3F, while Pete's tables above used 2F. I am assuming that's what created the pressure difference.

I'm looking for pressure in some smaller guages. like 28ga. 410 etc.

In the 50's American Rifleman article from which that graph was taken (note it was re-produced for this article, was originally preparred by the DuPont labs in the 20's as I recall) it was stated that Black Powder had reached the peak of its effiency in the last decades of the 1800's. A lot of newer Black Powders are simply not up to the oplder powders. The quality of the charcoal used plays a large part in this as I understand it. Note the Elephant is consistently below the GOEX in both velocity & pressure. No data is listed here for Swiss, which is generally of a higher grade. The diference between the 2F & 3F would of course play a small part, but should not account for differences of any where near this magnitude.

I have an electronic copy of an Article from Guns magazine, March 2000, by Holt Bodinson.
It lists test data from the 1960s:

82gr / 3dr FFF, 1 1/8oz 7.5, 1205fps, 4900psi
109grs/4dr FFF, 1 1/8oz 7.5, 6900psi (no velocity offered).

That's why I find pressures reaching as high as 10,000psi, even with FFF, so surprising.
RG

That graph is a redone version from the 1933 booklet published by Dupont, written by Coxe. He goes on about that chart for several pages.







Pete