Gowge:

DuaneinND is giving you exactly the right info. With shotguns (unlike rifles) the problems of excessive pressure begin when the shot goes into the "force cone' or taper from the chamber into the barrel itself. I hope you are not asking in some quiet way whether you can use modern loads in an old shotgun? If so, you have to give some more details before anyone wants to venture an answer.

Looking for suggestions here for the strongest auto, pump or other repeater action. What's your opinion? What is the maximum pressure the action can operate without failure?

THANKS!!

Would it be asking too much to know why you are looking for this information? For the most part with shotguns the barrel will burst before the action fails.

www.duanesguns.com