The SOLGW NTC Bolt Carrier Group represents the culmination of nearly 2 years of research and testing on advanced coatings optimized for extended service life high lubricity and best-in-class corrosion resistance. The NTC coating is extremely slick even without lubrication and excels at shedding carbon buildup.SOLGW OCKS (Optimized Carrier Key Screws) Bolt Carrier GroupMulti-caliber compatibility: 5.56 NATO .300 Blackout 6MM MAX and .350 LegendHP/MPI Tested C158 Bolt for enhanced durabilityPhosphate Extractor for reliable extractionChrome Plated Firing Pin and Gas KeyChrome Lined Gas Key and Carrier BoreNTC Coated Carrier Bolt Ejector and Cam PinIncludes OCKS (Optimized Carrier Key Screws) UpgradePerfect for high-volume shooters and suppressed use this BCG makes cleanup a breeze while delivering exceptional reliability and performance across multiple calibers.