9mm Bolt Carrier Group BCG Nickel Boron for GLOCK and COLT Mags, Full Ramp***Note: These BCG's require that a small amount of filing or machining on the bolt catch if used with CMMG style 9mm lowers as the CMMG style bolt catch interferes slightly with the bottom of the BCG when fully assembled causing the BCG to bind. See fifth product picture for reference and click on the link below about this issue.https://www.ar15.com/archive/topic.html?b=3&f=15&t=5548969MM Bolt carrier
group for your AR15 9MM upper. Nickel Boron exterior. The carrier includes the proper 9mm gas key. Gas key is secured to
carrier via USGI domestic mfg Grade 8 fasteners. These properly hardened parts insure a strong staking and
proper gas system functioning. Full ramp on carrier that works with standard rounded hammers eliminates the need for a special, more expensive bcg need for use with notched hammers. Fits and operates just fine in any standard AR-15 9mm upper receiver.