Did the English makers use a standard thread pitch for hammergun nipples? If not, what were some of the pitches in use for the part around the 1860-1880? Thank you.

BS,,,? I pulled the firing pin on my 1878 greener hammer gun I have apex tap and dies that are English and 5/16.x27 is close the problem is the greener threads are shallow and rounded .sirry not more help

I may just find some close to the other one, but American. The gun is a 12b Joseph Lang from 1867 that was modified to be sleeved as a rimfire. A big off center hole was bored into the left fence to accommodate an insert. I’m plugging said hole, and then milling for a new nipple and firing pin.

Bill,
mc started his answer with BS,,,? I think he is referring to "British Standard" thread form, which is rounded as he described. You may be able to find taps and dies at your local hobby shop.
Mike

Thank you. I have a BA set. They’re not in front of me, but I think they are smaller set. Will check.

I think the Whitworth thread form is also rounded, you might find one of those that is close enough.
Mike

An interesting topic ( I was going to say thread, but that could have caused confusion?).
Many gunmakers used what was readily available at the time, which could be BA or BC .
BC is British Cycle thread which was used extensively , especially by Birmingham gunmakers.

The Internet may be your friend ?
Lots of information on thread and threadforms .
A very good handbook is the catalogue available free from Tracey Tools Torquay England UK.

Simple answer .NO . Old British gunmakers never had " standard" anything on actions .