Replace all the springs with a fresh set. Aside from that, among the small parts there's nothing breakage-prone that isn't already commercially available (firing pin, extractor, etc.). As a collector I keep a small number of vintage parts on hand, but that is mostly to restore any new aquisition to its correct status. For example, I recently bought a nice WB Colt that was correct except for having a WW1 slide stop. Fortunately I already had a WW2 Colt slide stop in my parts box.
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D. Kamm
USGI M1911/M1911A1 Pistols Website
http://usgi1911.tripod.com
[This message has been edited by dsk (edited 11-17-2001).]