Jon: CIP Superior PROOF is 1370 BAR = 19,870 psi which is essentially the SAAMI standard. From
https://saami.org/wp-content/uploads/2019/01/SAAMI-Z299.2-Shotshell-Approved-2015-08-31.pdf Proof loads:
If a manufacturer uses a SAAMI proof loads, then the gun will be proofed by a lot of no less than 10 shots of ammo loaded to a maximum proof pressure of 20,500 psi +/- 900 – 4600 psi, or uber max of 25,100 PSI; and, will be similarly a MINIMUM average proof pressure of 19,000 PSI +/- 900 – 4600 psi for an absolute minimum proof of 14,400 PSI.
And it is important to recognize the acceptable deviation in both fps and psi
Load velocity can vary by +/- 90 fps for both game and target loads.
Load pressure
Maximum average pressure for 2 3/4" and 3” shotgun shells will be 11,500 PSI
+/- 900 psi, with some maximum extreme variability not to exceed an uber-max of 12,500 psi +/-900 psi
