FWIW:

The Rottweil shotshell brochure mentions the CIP service pressures for modern CIP standard proof cartridges in bars:

12 gauge: 740 bars

16 gauge: 780 bars

20 gauge: 820 bars

All figures in "piezo-electric"!

Here is a link (hope it works). The info is on page 7 of the brochure under "Playing IT Safe".

Rottweil Shotshell Brochure

Rottweil, as you all know is one of the most respected cartridge makers and make CIP tested cartridges.

All the best

Skeeterbd