Blackpowder Pressures from Sporting Guns and Gunpowders: Comprising a Selection from Reports of Experiments, and Other Articles Published in the "Field" Newspaper, Relative to Firearms and Explosives, Volumes 1-2, 1897



Definitive proof was 6 1/2 Drams Proof House Powder with 1 2/3 oz. No. 6 shot = 4 1/2 Long Tons LUP or about 14,000 psi.
6" Proof Pressure was not reported but looks to be about equal to 72 gr. C&H No. 2 T.S. (somewhat similar to FFFg) = 3.2 Tons = 9,632 psi

So what is the Mean Service Pressure suppose to be at 6 3/8"? CIP doesn't list a target number.

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