Remington New model No 4

Hi everybody,
I introduce myself, I am a Lionel French collector of U.S. weapons, I have already made some acquisitions on Gunbroker. I also made the restoration of "weapons (if not too complicated) I often search parts, I know some websites with you but maybe some of you on this forum can help me.
I can not find a hammer and Mainspring for Remigton new model No4, your advice and knowledge are welcome.
see you
Lionel