For me Jp gmr 13
Roughly 7 firing pins
1 bcm charging handle, the latch pin sheared
2 hammer springs in the 24c
1 non cotter pin style fp retaining pin (won't ever use this style again)
General maintenance I changed the extractor, ejector and scs o rings.
This is all through 3 seasons and a lot of rounds down range. So I would say i have had really good luck with mine.
Haven't trashed any mags or optics either.