Common parts to have on hand for field repares (aka good travel bag for out of town match, range etc.).
Options on a 50 year parts kit (assume one barrel, couple set of higher wear items etc.).
Update from search:
Earlier Posting on Spare Parts recommending spare bolt complete with firing pin, spring, hammer and hammer pin and extractor. Then a spare lower complete and a spare barrel like the one on the gun.
Edited by JTinIN, 22 August 2004 - 10:28 PM.