BCM has taken great care to ensure the best possible performance and interchangeability. However, due to the large operational range of 300 Blackout ammunition in the market place, BCM cannot guarantee function will all ammunition types in all conditions. These barrels were designed to run with a H3 buffer with high velocity ammo. If running subsonic ammunition, it is recommended to run your suppressor and a carbine buffer. Fine tuning may be required in limited instances based on ammo and buffer choices that work best for the desired application. BCM also recommends running the Crane O-ring (provided with all BCM Bolt Carrier Groups) over the extractor with 300 Blackout.
