Sandlapper: turn-of-the-century shotshell speed was often reported as "Average Velocity"; sometimes over 100 feet, sometimes over 40 yards.
The 3 Dram load "average velocity" would be about 1000 fps
G.T. Teasdale-Buckell,
Experts on Guns and Shooting, 1900
https://books.google.com/books?id=P7UrAAAAYAAJ&pg=PA235 1 1/8 oz. load comparisons. Pressure converted used Burrard’s formula
42 gr. = 3 Dram Bulk Nitro – 1” chamber pressure 7,985 psi / MV 1208 fps (1200)
45 1/2 gr. = 3 1/4 Dram – 9,730 psi / MV 1,274 fps (1255 fps SAAMI standard)
49 gr. = 3 1/2 Dram – 11,780 psi / 1,328 fps (1300 fps)
In a 1927 Western Cartridge Co. flyer “Super-X The Long Range Load” by Capt. Chas. Askins the 12g “Duck Load” (not specified but presumed to be 1 1/4 oz. Super-X “Field”) is described as 3 1/2 dram (38.5 gr. DuPont Oval Powder = 11 gr. / Dr. Eq.); at 1400 fps (at the muzzle rather than 3 feet) and
1000 fps average over 40 yards, with a breech pressure of 3 3/4 tons or about 8,400 psi + 10-14%
3” Super-X “Record” with 1 3/8 oz. at MV 1400 fps with 4.25 tons = 9,520 psi + 10-14%
Super-X 10g 1 5/8 oz. “about 4 1/2 Drams” No. 2 shot Full choke 32” barrel,
average velocity over 40 yds. 1030 fps; “up to 13,000 psi” by crushers = about 14,500 psi by modern transducers.
