Extractor and gas rings. Maybe extractor pin and cam pin if you have the tendency to lose stuff.
BGC and LPK are not needed.
I keep a lot of spare parts, but I dont think That I need all of them. With all spare parts that I have, I can probably build another AR15 if I buy another lower lol.......
Essential parts are:
Gas ring (minimum 3)
Extractor, extractor spring (or a spare bolt)
Firing pin
Cam pin
Disconector
Hammer
Hammer spring
Except for the bolt all theses parts are cheap to buy and very usefull if you are a high volume shooter.
Too complicated. Just buy another AR.



























