More on the small bore gun; from Capt. Charles Askins' and E.M. Sweeley's “Ballistics of the Shotgun” series in Outdoor Life
June, 1921 “Killing Range of the 20 Gauge”
https://archive.org/details/sim_outdoor-life_1921-06_47_6/page/386/mode/2up

January 1923 “Developing A Duck Load In The 20 Bore”
https://archive.org/details/sim_outdoor-life_1923-01_51_1/page/30/mode/2up

February. “Duck Loads in the 20 Bore II”
https://archive.org/details/sim_outdoor-life_1923-02_51_2/page/112/mode/2up

August 1922, “20 & 28 Gauge Pressures and Velocities”
https://archive.org/details/sim_outdoor-life_1922-08_50_2/page/120/mode/2up

20 gauge with DuPont Bulk. Plus 10 - 14%
7/8 oz.
2 1/4 Dr. Eq. = 10,550 psi
2 1/2 Dr. Eq. = 11,715 psi
1 oz.
2 1/4 Dr. Eq. = 12,029 psi
2 1/2 Dr. Eq. = 13,373 psi

28 gauge
5/8 oz. 2 Dr. Eq. = 8,714 psi
3/4 oz. 2 Dr. Eq. = 10,259 psi
3/4 oz. 2 1/8 Dr. Eq. = 10,998 psi
7/8 oz. 2 Dr. Eq. = 12,387 psi

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