Progressive Burning DuPont Improved Military Rifle (I.M.R.) Powders were introduced in 1914. DuPont Oval was developed for the 1922 introduction of Western Cartridge Company’s 12g ‘Super-X Field’ 2 3/4” 1 1/4 oz. 3 3/4 Dram Equiv. shell. The Peters Cartridge Co. ‘High Velocity’, United States Cartridge Co. ‘Ajax Heavies Long-Range’, Remington Kleanbore ‘Nitro Express Extra Long Range’ (the boxes were marked “3 3/4 Drs. Equiv.”), and Winchester ‘Super Speed’ (also marked 3 3/4 Dr. Eq.) loads soon followed.
Western’s 3 inch “Record” with 1 3/8 oz. of shot was released in 1923.

Western Cartridge Co. never marked the Super-X “Field” or “Record” boxes with “Dr. Eq.” stating only “Maximum Load”.

In c. 1927-1935 Western Cartridge Co. pamphlets “Super-X The Long-Range Load” (courtesy of Michael Harris), Capt. Chas. Askins listed the loads, some muzzle velocities (modern 3’ velocity would be about 70 fps less), some pressures, with extensive pattern testing.



12g 2 3/4” Super-X “Field”
1 1/4 oz. with measured 38 1/2 gr. DuPont Oval (11 gr. / Dr. Eq), 3 3/4 Tons = 11,480 PSI with MV 1400 fps, No. 4 shot; 165 pellets in 1 1/4 oz.
Full choke. 30” circle pattern.
Super Fox “special double gun”
40 yds. = 148 pellets = 90%
55 yds. = 118 pellets = 71%
60 yds. = 97 pellets = 59%
70 yds. = 65 pellets = 40%
G.E. Lewis Magnum at 40 yds. = 138 pellets = 84%
Ithaca at 40 yds. = 127 pellets = 77%
Parker 10g at 40 yds. = 138 pellets = 84%

No. 6 shot (260 pellets in 1 1/4 oz.) at 40 yds.
Super Fox – 244 = 94%
Fox Featherweight – 214 = 82%
Lewis – 216 = 83%
60 yds.
Super Fox – 153 = 59%
Lewis – 160 = 61.5%
Super Fox at 70 yds. – 120 = 48%

No. 2 in Lewis gun
60 yds. – 71 = 65%
70 yds. – 37 = 34%
Super Fox at 75 yds. – 46 = 42%

3” Super-X “Record” with 1 3/8 oz. at MV 1400 fps with 4.25 Tons psi = 13,160 psi
No. 4 – 190 pellets per 1 3/8 oz.
No. 2 – 130 pellets
Smith Long Range
No. 4 at 40 yds – 87%
No. 4 at 60 yds. – 53%
No. 4 at 80 yds. – 26% (one shot)
No. 2 at 40 yds. – 87%
No. 2 at 60 yds. – 53.5%

Pattern testing by David Williamson with .042" choke 32" LRWF at a measured 80 yards using 3” Winchester (plastic) hull with 38.35 grains of Blue Dot, Winchester 209 primer, Winchester AASL wad, and 1 3/8 ounces of #5 nickel plated shot. The average number of pellets was 246 and measured weight 1.353 ounce.
Pattern % in 30" circle: 5.3 = 13 pellets, 8.1 = 20 pellets & 8.5 = 21 pellets.

Hunter Arms Co. Pressure Curve dated June 10, 1929, from the McCracken Research Library, Buffalo Bill Center of the West (found by Gary Rennles) and used by permission
http://library.centerofthewest.org/cdm/singleitem/collection/WRAC/id/8149/rec/107
1” peak pressures by lead crushers so 10 – 14% higher by transducers
12g 3” “Record” 1 3/8 oz. shot = 13,250 psi
12g 2 3/4” “Field” 1 1/4 oz. shot = 10,750 psi