Scroll down to the bottom here for some modern load pressures
https://docs.google.com/document/d/1F2sQuPm05IE4VWYYnCkvuXmYEzQoWd_SQgaAfUOZEFU/preview
Most "Dove and Quail" loads are NOT low pressure
Herters for Cabela’s by Cheddite, Italy
http://www.chedditeitaly.com/en/index.php
Field & Target 1 oz. - 1290 psi
Select Field Dove & Quail 1 oz. - 1250 psi

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