Just an addendum to this, i came across a blog of an english gunsmith who works in America, repairing very high end british shotguns. He has in the course of his work to make and fit and fit leaf springs. The steel he uses is plain old 01, also known as drill rod or gauge plate. He of course hardens and tempers the metal to spring temper. To see his blog google vicknairrestorations.
Edited By ronan walsh on 13/02/2017 21:52:08