Thank you, Dennis. I noticed a difference over the years so I am assuming that mine has worn to that point. It is one of the ones without a barrel selector and always fires the right barrel first, so it makes sense that would be the barrel that came off face first.
If I'm understanding you, you're saying that fitting of the barrel breeches to the breech face was not a big priority with the BSSs?
Anyway, it is obvious that an oversized replacement pin would fix the issue because a .003" shim on the pin does so. I will be contacting you privately to discuss this more, if agreeable to you.
I may not have been clear about the pin that works out. It is not the hinge pin, but a small pin that goes through the action body towards the rear. I will try loctite, just on the ends though, so as not to lock up some internal parts.
Best to you, SRH