300BLK has proven itself to be an incredibly capable round in a variety of applications, from close quarters to mid-range and ammo loadings optimized for subsonic/suppressed as well as supersonic, there is use for almost every need. Whether youre looking to swap your current AR15 upper to quickly switch to 300BLK or looking to top off a new build, this 8 BANSHEE upper group is sure to satisfy anyone looking for one of the most compact and stylish 300BLK upper groups made today. Specifications for CMMG Mk4 .300BLK 8in Banshee Upper Group Receiver: Manufacturer: CMMG Caliber: .300 AAC Blackout Barrel Profile: Medium Tapered Barrel Twist Rate: 1-7 Threads per Inch: 5/8x24 Finish: Cerakote Gas Block Journal Size-Diameter: .750 in Gun Rail: M-LOK Gun Type: Rifle Gun Make: CMMG Gun Model: CMMG Mk4 Magazine Included: No Package Contents: CMMG Mk4 .300BLK 8in Banshee Upper Group Receiver What firearm models does the manufacturer say CMMG Mk4 .300BLK 8in Banshee Upper Group Receiver is compatible with? The manufacturer suggests that CMMG Mk4 .300BLK 8in Banshee Upper Group Receiver is compatible with CMMG Mk4