Identification
Search by what it is called now, what it was called then, or your best guess at the spelling. All three resolve to the same entry.
Matches
The reference
The component itself, described once and linked to every arm it appears on. This is where the identification notes live.
Matched “battery”, a recorded name for Frizzen. Period, regional and trade terms are all filed against the same entry, so either word finds it.
The steel struck by the flint. Called the battery, or confusingly the hammer, in British usage.
Matched “battery spring”, a recorded name for Frizzen Spring. Period, regional and trade terms are all filed against the same entry, so either word finds it.
Returns the frizzen over the pan and holds it closed.
None of these it? Describe it to Butch — a photograph and a sentence is enough — or post it on the wanted board so a dealer can offer you one.