Bruce,
Interesting table. I have been collecting old ammunition paper for some years now, seeking information about pressures of the early loads. According to my DuPont Smokeless Shotgun Powders booklets from the 1920s and 30s, those 3 1/2 dram, 1 1/4 ounce 12-gauge loads of bulk smokeless powder were pretty high pressure, 11,700 lbs with DuPont bulk smokeless, 11,800 lbs with Schultze. The equivalent in dense smokeless powders, 28-grains of Ballistite, 12,600 lbs. With the introduction of their DuPont Oval progressive burning smokeless powders, in the early 1920s, 40-grains would move that 1 1/4 ounce out at a velocity of 981 feet per second over 40 yards at 9400 lbs.
Dave
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