Models View all M4A1 - Bolt Carrier - Bolt - Enlarged Extractor with no Locking lug 28 810 0 M4A1 - Bolt Carrier - Bolt - Bolt(with no extractor cut) 33 1105 3 M16 trigger 74 3474 4 M4A1 - Bolt Carrier - Bolt Carrier - Firing Pin1 15 737 0 M4A1 - Bolt Carrier - Bolt - Extractor1 16 737 0 M4A1 - Bolt Carrier - Bolt Carrier- Bolt Cam Pin 18 777 5