Faxon Firearms FF9MMBCGCNITRIDE: Purpose-built for 9mm AR-15 pistol caliber carbines, our Generation 2 PCC Blow-Back carriers keep the features of our first BCG with modern improvements. We maintain the dual COLT/GLOCK compatible geometry, user-removable weight and full-auto compatibility. We maintain a \"ramped\" bottom so any common trigger can be used, ideal for competitive shooters and plinkers alike. The extractor has been upgraded to an AR-15 pivoted and sprung option. For ease of disassembly, a standard firing pin cotter pin is used, and to ensure long-life, the carrier key is separate from the charging surface ensuring that the carrier stands up to any vigorous action.Features Glock/Colt style lower receivers compatible; fully heat treated; external M-16 style extractor; Compatible with- Removable Carrier Weight-JP Enterprises and similar buffer systems, MP5 magazine lower receivers, dust cover and M16 (full-auto)compatible.