This is the pressure curve from “Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics” by Wallace H Coxe; E.I. du Pont de Nemours & Co.,
1927, a DuPont Oval Pamphlet, p.20.
Dram Eq. is listed in the text as 3 but is more likely 3 3/4 compared to the 1928 data.
Charge was 1 1/4 oz. Pressure is expressed in Long Tons.
“All Powders Loaded To Develop The Same Energy” was added to a similar chart in
1931.
Using Burrard’s estimated Tons Lead Crusher Pressure (Cp) conversion to PSI (pound force per square inch): (Cp x 1.5) - .5 = TSI; TSI X 2240 = PSI
Ballistite maximum pressure at 1” was 4.9 Long Tons = 15,344 psi
Schultze at 1 3/4” was 4.5 Long Tons = 14,000 psi
DuPont Bulk at 1 2/3” was 4.1 Long Tons = 12,656 psi
FFFg (likely proof load) at 1 1/2” was 3.8 Long Tons = 11,648 psi
DuPont Oval at 2” was 3.5 Long Tons = 10,640 psi
Could you please scan and post the chart to which Askins was referring in
1929?
This is the
1933 chart; now expressed as
PSI measured by LUP.
The pressure curves are for a 3 Dr. Eq. 1 1/4 oz. load.
Pressure by modern piezo transducers would be 10-14% higher.
DuPont Bulk = 9,600 psi
FFFg = 9,000 psi
DuPont Oval = 8,700 psi
DuPont MX = 9,800 psi