William Bruette, Guncraft: Guns, Ammunition, Wing & Trap Shooting, 1912
https://books.google.com/books?id=5g51K93as84C&pg=PA209&dq
Pressures converted from long tons/sq. inch to psi by Burrards formula so do NOT require adding 10-14%

Curtis & Harveys (42 gr. = 3 Dram) Amberite
12g 2 1/2 case 47 gr. (3 1/3 Dram) 1 1/4 oz. shot = 11,480 psi
12g 2 1/2 case 42 gr. (3 Dram) 1 1/8 oz. = 8,960 psi
16g 2 1/2 case 36 gr. (2 1/2 Dram) 15/16 oz. = 10,640 psi
20g 2 1/2 case 33 gr. (2 1/3 Dram) 13/16 oz. = 11,648 psi

Curtis & Harveys Smokeless Diamond (33 gr. = 3 Dram)
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
16g 2 1/2 case 28 gr. (2 1/2 Dram) 15/16 oz. = 11,480 psi
20g 2 1/2 case 26 gr. (2 1/3 Dram) 13/16 oz. = 12,320 psi

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