The extractor slot is machined , gas port is drilled, & the handguard retainer slot is cut. Trunnion journal size is .868" so be sure the trunnion has a hole of .867" or smaller. A press fit of .001" to .0015 is what you want. 4140 material with 1-6 twist. The outside is in the white.
This item is made in the United States and counts as a 922r compliant part.