mainspring identification?

[G.T.]

Hello to all, I have been diligently repairing Luger magazines and sometimes lugers over the last few years, and I'm getting to where I've seen quite a bit of weird stuff? Handmade, homemade, shade tree gunsmith kinda stuff? I have learned that the three most important aspects for good function are, correct mainspring, new or excellent extractor spring, and proper magazine spring, in a good to excellent magazine. Well, the question I have here, is about mainsprings.. I remember seeing, in either an early book by Datig, or Smith, a small chart where he list some of the more common spring dimensions... As I no longer have the books, I was wondering if someone in the membership could look for me? The spring I have has 17 coils, is approx. 2.900" long, and has a wire dia. of .057" Let me know if anyone has any idea as to it's origin??... Best to all, til...latr....GT...