I am really not sure of exactly what they did after it all fell apart with WWII and after the takeover, but it has been stated that the Czech proof facility carried on as before. Per the December 17th, 1931 proof law which became effective on the 1st of January 1932 and date to December 22, 1931, Black powder was still used in the preliminary proof of unfinished tubes to attain a pressure of 15,645 PSI. But then it says that arms that use semi-smokeless must be proofed with semi-smokeless, so I guess both powders had the same target pressure? Then the 2nd and obligatory proof effort with tubes in the white, a target pressure of 11,378 PSI was the target. Last, then 3rd compulsory for a tube in the final state but not yet blued, mimicked the >>international standards<< of 8818 PSI. In the event that a tube stepped up to the plate for the 4th compulsory proof, that target pressure was 14,223 PSI for case length 65mm or less. The N(Nitro) in a Shield is the 4th mark.
Serbus,
Raimey
rse