2a thread class right-hand 0.365" thread length flat fillister head style 40 thread quantity per inch navy special project passivate screw surface treated head threaded .112-40 unjc-2b depth .180/.200 unjc thread series
2a thread class right-hand 0.151" thread length hexagon extended washer head style 40 thread quantity per inch passivate surface treated unc thread series
Used on barrell assembly, internal auxiliary launcher. 3a thread class 20 thread quantity per inch screw, cap, socket head, self locking (requested name) unrc thread series