....As you have learned, are scarse as hens teeth. I think that many who are saying they have ASM parts really have recently manufactured parts which they think will fit.
People like VTI and DGW go through their parts quick enough that the stock purges itself. The small ones like Winchester Sutler for Euroarms (ASP) parts and Deer Creek for ASM may still have some old stock laying around.
I picked up a Euroarms cylinder for an 1851 from Winchester Sutler a coupla years ago. It was the last one he had and he had to go scrounging around his barn to find it.
I never asked him about ASM parts because his forte is ASP.
You might try those two
Deer Creek Waldron Indiana - 765-525-6181
Winchester Sutler - Winchester, VA - 540 888-3595
Deer Creek went into some hard times about a year ana half ago, I think because of health problems. It appears that a young man (perhaps the son) has taken over and the operation is a good bit more useful now.
Winchester Sutler will likely be answered by a woman who will yell for someone else when you ask a technical question.
My reading of history convinces me that most bad government results from too much government. Thomas Jefferson