That's the point, make sure the weapon is fixed and play with the old parts. That is actually how I started gunsmithing over 50 years ago. Sure, things will get screwed up, but how else does one learn? At least in this day and time several forms of information is available to research. When I started I had old time coal fired blacksmith shop with a retired blacksmith / gunsmith as a mentor. I have put the spring in a lot of old springs with a propane torch and oil, ashes or sand. It can be done relatively cheap and inexpensive.