Custer said:
What would be the best source to buy an extractor spring?
Kvar, Tapco, CDNN, Global trades, and there is a place that sells only Chinese AK parts for Polytechs and Norinco.
http://www.polytechparts.com
Numrich gun parts is a great place for everything and anything. I just got their catalog yesterday. 1200 pages of diagrams and parts schematics for $12.95.
You need to get that catalog for the diagrams alone!