I was chasing something else as usual & noticed these pressure values in a "TW" VEB Fahrzeug und Jagdwaffenwerk Ernst Thälmann, Suhl DDR catagloue. So this gives us an idea of what to compare. 3 - 4 pages up from the bottom - gives circa 1975 date.

http://www.germanhuntingguns.com/archives/veb-ernst-thalmann-werke/

Kalibre 12 - 850 Bar
Kalibre 16 - 900 Bar
Kalibre 20 - 950 Bar

Any >>bar<< conversion folks that can push that towards PSI??

Also they give that for a few more quid they will attempt to blow it up @ 1200 Bar:

>>Auf Wunsch wird gengen Mehrpreis auch die verstärkte Beschußprüfung mit 1200 bar durchgeführt.<<


Cheers,

Raimey
rse

https://www.unitconverters.net/pressure/bar-to-psi.htm

850 Bar converts to 12328.207707 PSI

"On request, at extra cost, the 1200 BAR bursting test will result in the surcharge"??? Der Fuchs