Scroll down to the bottom here for a few modern load pressures
https://docs.google.com/document/d/1F2sQuPm05IE4VWYYnCkvuXmYEzQoWd_SQgaAfUOZEFU/preview

Herters for Cabela’s are by Cheddite and pressures are not reported
http://www.chedditeitaly.com/en/index.php

Scroll down about 1/3 here regarding Bell's long shells in short chambers study
https://docs.google.com/document/d/1ZIo0y746UsSRZIgRuuxwAbZjSBHitO_EanvwLYc-kGA/edit