I have been slowly retrofitting an old Westerfield thotgun, and in the
process I put to much strain on the trigger pivot pin and broke into 3
pieces. It looks like brass to me. The raw surfaces are very shiny like
brass, and have no hint of the pastiness I sometimes see in bronze. It
measures at about .090 as near as I can measure a twisted broken pin part
about an 1/8 inch long. I can't find any bronze that small, and the nearest
brass piece I can find from McMaster is 3/32 (0.09375). It looks like the
only answer I am going to have is to polish down a piece of 3/32 brass rod.
The trigger is a pretty integral part of this mechanism with a simple hook
that holds back the firing pin when you close the bolt, so I am trying to
decide which alloy is going to give the best life for this application. The
gun is over 60 years old, so whatever the original pin was it did a pretty
good job.