I've got an idea what it might be and I don't believe it's been mentioned yet in this thread. Look to see if your trigger pin is being tightly held in place by the width of the opening in the stock. If it slips just enough to allow the pin to disengage the trigger housing at one end, what you've shown can happen. I don't have time to explain it right now, but I'll post pictures below and a link to my thread that should explain it. If the trigger pin is a sloppy fit in the TH or in the trigger, I suppose it would do the same thing. - Bob
Hmmm! I can't find a link to my thread. Maybe I just imagined that I made one on this "jamming" with my Underwood? Painter777 could probably find it for me. He knows how to search this forum better than I do!
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