That is the very problem I was trying to illustrate. I just couldn't seem put it the way you did. I have had to send the frame back to T/C with every barrel I have aquired. Each time it has been returned in proper working order, and the barrels I had previously still worked. The only thing I noticed upon disassembly, that was the least bit questionable, was that the front-facing surface of the hammer block had been polished. So much so, that it was opening a slight amount of the hole into which the spring goes into. I could not see any wear on the spring though, even under a magnifying glass. Stretching the hammer block spring had no effect. I sent a note with it this time asking T/C to review the history on this frame (they do keep records, don't they?), and to please check the frame out for any problems; beside just fitting this barrel. Maybe I'll find something out this time. It's just a PITA, not to mention the $40.00 or so it costs each time I have to send it back.,,,,,,,,,,,,,,,,,,,,,,,,Bug.
Oh, yeah, The firing pins look & move good, and I did replace the older, 2-legged spring with a newer 1-legged one......B.