Cmmg Inc. CMMG Banshee Mk4 AR-15 Upper Group .338 ARC 10.5" Barrel Black. To maximize parts compatibility 338 ARC utilizes the same bolt as 6.5 Grendel AR15s. For those that like to load their own ammo CMMG 338 ARC barrels feature a slower 18 twist rate to allow the use of more traditional construction .338 caliber projectiles. Pistol options include DISSENT models with 6.5 10.5 and 16.1 barrel lengths and BANSHEE models with 10.5 barrels. Platform Mk4Caliber .338 ARCOperating System Compact Action-Direct ImpingementBarrel Length 10.5Barrel Twist 18Barrel Contour MTBarrel Material 4140CM Nitride FinishBarrel Twist 18Muzzle Device CMMG ZEROED Linear CompensatorMuzzle Thread 5/8 x 24Gas Block Non-Adjustable 0.750Upper Receiver Mk4 Billet 6061 T6 AluminumHand Guard EML9Finish CerakoteCharging Handle Dissent Side ChargerWeight 3.1 lbs Specifications for CMMG Banshee Mk4 AR-15 Upper Group .338 ARC 10.5 Barrel Black 867B8328: Manufacturer: CMMG Caliber: .338 ARC Barrel Length: 10.5 in Barrel Profile: Medium Taper Gas System Length: Pistol Length Barrel Twist Rate: 1-8 Firearms Threads Per Inch: 5/8x24 Handguard Type: Free-Float Muzzle Device: CMMG ZEROED SVB Brake Finish: Cerakote Nitride Color: Armor Black Fabric/Material: 6061-T6 Aluminum Model: Banshee Mk4 Gas Block Journal Size-Diameter: .750 in Handguard Length: 9 in Handguard Style: M-LOK w/ Top Picatinny Rail System Gun Rail: Picatinny M-LOK Gun Make: CMMG Weight: 3.1 lb Barrel Material: 4140 Chrome Moly Gas System Type: Direct Impingement Magazine Included: No Package Contents: CMMG Banshee Mk4 AR-15 Upper Group .338 ARC 10.5 Barrel Black Made to combine the prowess of the AR15 platform with the stopping power of a large bore caliber 338 ARC strives to emulate the sub or supersonic versatility of the now ubiquitous 300 BLK cartridge with more energy on target and less gas system tuning when switching from suppressed to unsuppressed. To maximize parts compatibility 338 ARC utilizes the same bolt as 6.5 Grendel AR15s. For those that like to load their own ammo CMMG 338 ARC barrels feature a slower 18 twist rate to allow the use of more traditional construction .338 caliber projectiles. Pistol options include DISSENT models with 6.5 10.5 and 16.1 barrel lengths and BANSHEE models with 10.5 barrels. Platform Mk4Caliber .338 ARCOperating System Compact Action-Direct ImpingementBarrel Length 10.5Barrel Twist 18Barrel Contour MTBarrel Material 4140CM Nitride FinishBarrel Twist 18Muzzle Device CMMG ZEROED Linear CompensatorMuzzle Thread 5/8 x 24Gas Block Non-Adjustable 0.750Upper Receiver Mk4 Billet 6061 T6 AluminumHand Guard EML9Finish CerakoteCharging Handle Dissent Side ChargerWeight 3.1 lbs 34B8D0F-AB