Are these standard AR parts or RDB specific? Any kit that has most of this?AR bolt gas rings for piston
AR extractor donuts for part 310
Firing pin retaining pin
gas valve detent spring
but stock screws
Pic rail mount screws
Those two parts, the gas rings and donut, have been "discovered" to be very similar to the parts supplied by KT and have been fitted to RDBs.Are these standard AR parts or RDB specific? Any kit that has most of this?