Thanks Gary. At this point I don't see a need to take the lock apart. It is clean and functioning well.
The broken nipple has been removed. I see that S&S has what I think are originals. is that the best bet for a source? are there any new made nipples?
I have not been a black powder person. it appears that there are only a few types of nipple and they are based on the cap size. Is that correct? It also seems that all of the nipples available in the box stores are intended for the reproduction arms. Other than an S&S type place are there good sources for nipples threaded for an original american rifle.