I think you guys have covered just about all the likely causes. My Trojan had the same kind of problem - likely many, many 2 3/4 promo and target rounds through it as someone's skeet gun, not thinking about it having 2 1/2 inch chambers. I had it glued up & bedded. The gunsmith (who had a good reputation) decided to add a brass rod on his own (one of several reasons I won't be going back to him), but on that gun (which already has an extension), it's no big deal.
Go read Salopian's thread on modern wood glues....
If I ever hit the lottery, I'll get a new stock made.
