Thank you Tom. JayCee provided this information, in the other thread, from 1920 for Preliminary Proof

[Linked Image from photos.smugmug.com]

12g
-First proof: 11 grams of BPnº2 and 70 grams of nº8 shot for 941 kg/cm2 = 13,384 psi
-Finished barrels: 10 grams BPnº2 and 60 grams of nº8 shot for 791 kg/cm2 = 11,250 psi
-Superior proof: 14.5 grams BPnº2 and 75 grams of nº8 shot for 1133 kg/cm2 = 16,115 psi
-Double proof: 20 grams BPnº2 and 120 grams of nº8 shot for 1441 kg/cm2 = 20,500 psi
-Triple proof: 30 grams BPnº2 and 180 grams of nº8 shot for 1726 kg/cm2 = 24,550 psi
The BPnº2 is called in French "Poudre Noire Forte Nº2.

These numbers are different; from https://www.shotguns.se/html/france.html
14,223 psi = 1000 Kg/mm2 Provisional Proof
16,356 psi = 1150 Kg/mm2 Reinforced Proof
17,779 psi = 1250 Kg/mm2 Double Proof

https://sites.google.com/a/damascusknowledge.com/www/home