Rainier Arms Match 300BLK Barrel 14.5in 1-8 Twist 5/8x24 Silver Small. They are able to reach their goal by sourcing a very high end barrel blank at an affordable price. They start off using a high precision match blank in 1:8 twist machine it to the highest quality you have a barrel that is the best value hands down in the industry. Specifications for Rainier Arms AR Match 300BLK Barrel: Manufacturer: Rainier Arms Color: Silver Finish: Bead Blasted Fabric/Material: Stainless Steel Caliber: .300 AAC Blackout Barrel Profile: M4 Gas System Length: Pistol Length Gas Block Journal Size-Diameter: .750 in Threads per Inch: 5/8x24 Barrel Twist Rate: 1-8 Gun Make: AR Platform Gun Model: AR-15 Package Contents: Rainier Arms Match 300BLK Barrel What firearm models does the manufacturer say Rainier Arms AR Match 300BLK Barrel is compatible with? The manufacturer says that Rainier Arms AR Match 300BLK Barrel is compatible with AR-15Rainier Arms RAB-M-300-145-P-NF-SAT: Match 300BLK Barrel 14.5in 1-8 Twist 5/8x24 Silver Small