[brno284]

Many lathes are not equipped to cut metric threads as ready as standard/Imperial. I think this is a bigger limiting factor than the gunsmith not wanting to. You can do them on most lathes but you cannot lose track of the revolutions on your thread engagement dial. Its easy enough to do but I prefer cutting standard threads for this reason with my current lathe. For me I have to change my gears as well so when 95% of the work is standard threads its easy to turn away 5% of business.

If I am accurizing a Metric threaded receiver I will set up on the mill and sometimes re-cut the threads to standard 1-16 TPI but this starts getting time consuming/costly.