Need help with a bacon .31 cal cap and ball

[Gun hog]

I need to build a mainspring for what I think is a first model bacon .31 cal. All the pics I can find online show the tip of the spring at the hammer stirup but the grip is covering the rest. I want to make it as accurately as possible. Can anyone here help with a picture? Thanks in advance

 

[sail32]

This might be a place to start as well as other US Civil War forums.

https://civilwartalk.com/threads/revolver-type.127180/

http://www.littlegun.info/arme americaine/artisan b/a bacon gb.htm

Book = http://www.baconfirearms.com/NutterReview.html