Bear Creek Arsenal BC15 .300AAC 16in Right Upper Receiver Heavy Carbine 1-8 5/8x24 Flash Hide Parkerized FDE. This BCA AR-15 complete 300 Blackout rifle length upper has a 16'' heavy barrel with a 416R stainless steel finish and features a 1:8 twist rate with a carbine length gas system. It includes the BCA Talon 15'' MLOK split rail an M4 flat-top 7075 billet aluminum upper receiver a BCA bolt carrier group a flash hider and a side charging (Gen 2) handle (patent protected). This 300 Blackout upper is compatible with any mil-spec AR-15 lower. Specifications for Bear Creek Arsenal BC-15 .300 Blackout 16in Right Side Charging Upper Receiver: Manufacturer: Bear Creek Arsenal Caliber: .300 AAC Blackout Barrel Length: 16 in Barrel Profile: Heavy Barrel Twist Rate: 1-8 Threads per Inch: 5/8x24 Muzzle Device: Flash Hider Gun Model: AR-15 Handguard Length: 15 in Gun Rail: M-LOK Gun Make: AR Platform Barrel Material: 4150 Chrome Moly Vanadium Weight: 5.5 lb Flutes: No Package Contents: Bear Creek Arsenal BC-15 .300 Blackout 16in Right Side Charging Upper Receiver What firearm models does the manufacturer say Bear Creek Arsenal BC-15 .300 Blackout 16in Right Side Charging Upper Receiver is compatible with? The manufacturer suggests that Bear Creek Arsenal BC-15 .300 Blackout 16in Right Side Charging Upper Receiver is compatible with AR-15Bear Creek Arsenal UASCC5007300CHB161875015FDESR: BC15 .300AAC 16in Right Upper Receiver Heavy Carbine 1-8 5/8x24 Flash Hide Parkerized FDE