William Bruette, in Guncraft: Guns, Ammunition, Wing & Trap Shooting, 1912 listed 2 heavy loads; note in a 2 1/2" case.
Pressure at the muzzle would be < 1000 psi
Curtis & Harvey’s (42 gr. = 3 Dram) Amberite
12g 2 1/2” case 47 gr. (3 1/3 Dram) 1 1/4 oz. shot = 11,480 psi by Burrard's conversion
Curtis & Harvey’s Smokeless Diamond (33 gr. = 3 Dram)
12g 2 1/2” case 39 gr. (3 1/2 Dram) 1 3/16 oz. = 11,984 psi
1 1/4 oz. 3 1/4 Dr. Eq. = 1220 fps
1 1/4 oz. 3 1/2 Dr. Eq. = 1275 fps
Please do share the pattern results!
