Update: I just removed the tumbler and this is what it looks like. The shaft itself is not twisted so that crosses that off. I still can’t tell if that shaft and tumbler are made as one piece or if the shaft is fit inside. I know on some guns that shaft is threaded but I don’t want to mess around and break anything. Does that shaft look to be lined up correctly?

The tumbler is all one piece.

Maybe the square shaft or even hole was built up with weldment and when fit back the angles were just a bit off.

Quite possible. This is the tumblers side by side. The picture doesn’t do a great job but you can see the square shafts are off. All the rest of the geometry is correct

Do they both have the same three-digit number stamped on them?






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The last picture shows the problem. Now as to the fix.....

There are no numbers on either of the tumblers, the closest numbers are on the bridles, locks, and hammers and they all match

Just a thought but I'd check the firing pin for proper length and shorten it a little if it would still function properly. It may not be the original firing pin.

Update: I definitely found the problem. Upon closer inspection, There appears to have been a stress crack at the base of the square shaft and that weakened it and allowed it to shear/twist at the base of the square end. Only the end is affected, and I can definitely see a small twist at the very base. I can probably repair this but does anybody happen to have a left tumbler laying around they would be willing to part with? That sure would be easier.

Good to see you found the issue.

I have many tumblers on hand.