see the article about the 90,000 rounds of use in the tutorials and information section for a good list of a spare parts "kit" that idpasteyr and his wife keep on hand.
As a more bare bones kit (let's face it you not going to shoot 20k rounds this year and take your steyr to a national match like they do)....
extractor assembly.
guide rod and recoil spring.
any spring or pin that you remove for deep cleaning (i can say from experience it sucks to have a gun down because you lost a spring).
these will get you through 90% of situations that will put your gun out of commission IMHO, and not have you sitting w/ hundreds of dollars of parts in the garage collecting dust.
Also a note to share w/ all of you regarding the new rounded pin used in the A1 extractors. In my conversation w/ Allan (the smith) at SAI in GA I asked about purchasing an A1 extractor assembly to have one as a spare on hand; he said the new rounded pins do not work any better, the change was not any kind of correction it was purely a matter of the rounded pin saves some money in production because they don't have to grind the bevel into the end. Even the repair center uses the beveled pin as they don't have any of the rounded ones (the only way to get one is in a new A1).
