In 1894, John Hall & Son introduced “Cannonite”, manufactured by the War and Sporting Smokeless Powder Co. The company was acquired by Curtis & Harvey in 1896 and the powder became “Smokeless Diamond” in 1903.

1896 UK Rules of Proof Service Charges for Nitro Powder
https://books.google.com/books?id=inQCAAAAYAAJ&pg=PA7

[Linked Image from photos.smugmug.com]

William Bruette, Guncraft: Guns, Ammunition, Wing & Trap Shooting, 1912
https://books.google.com/books?id=5g51K93as84C&pg=PA210&dq
Pressures converted from long tons/sq. inch to psi by Burrard’s formula
Curtis & Harvey’s Smokeless Diamond is a 33 gr. = 3 Dram powder. It is not equivalent by volume to Black Powder and must be weighed
12g 2 1/2” case 39 gr. (3 1/2 Dram) 1 3/16 oz. = 11,984 psi
12g 2 1/2” case 33 gr. (3 Dram) 1 1/8 oz. = 9,632 psi
12g 2 1/2” case 33 gr. (3 Dram) 1 oz. = 8,288 psi

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