I have worked in an aerospace materials laboratory for 35 years. I know a bunch of world class engineers. I do not forge, I form, I shape and I machine. I have been building guns for 40 years. I have done machining for 40 years. I have done firearms engraving for 35 years. So far that makes me 150 years old. I have access to lots of equipment to analyze steels and to heat treat them. I'm getting back into flintlocks. May I have your forming suggestions? I plan to form V springs. NEVER use a car spring that has broken in use. It's a bad piece of metal. Most flat springs are 6150 but some are 9255. There are spring benders locally. I will gladly buy their scraps rather than put many hours into an old piece of metal. That is not to say that most of the old springs out there are not just fine but they have been fatigued over a lot of miles. Every bump in the road is a stress.