Post 1939 for 16 bore up to 70mm, a cartridge must generate a chamber pressure at the 1st node of 12090 PSI. For each additional 5mm, an additional pressure of 1422 PSI must be seen @ the 1st node.

16 bore & larger smoothbores must experience a pressure of at least 11379 PSI on some International apparatus that is some gas mechanism?

Black powder loads with Nr. 3 shot must attain a pressure of 9956 PSI @ node 1.


Cheers,

Raimey
rse