Rainier Arms Ultramatch MOD2 Barrel AR-15 .223 Wylde 18 in 1-7.5 Twist 1/2x28 Rifle Length Satin Silver. Their goal is to mass produce them to bring them to market at the most competitive prices. They wanted the best balance between accuracy while keeping the weight down as much as possible. Specifications for Rainier Arms AR Ultramatch MOD2 .223 Wylde Barrel: Manufacturer: Rainier Arms Fabric/Material: Stainless Steel Caliber: .223 Wylde Barrel Profile: M4 Gas Block Journal Size-Diameter: .750 in Threads per Inch: 1/2x28 Barrel Twist Rate: 1-7.5 Flutes: Yes Gun Make: AR Platform Gun Model: AR-15 Condition: New Package Contents: Rainier Arms Ultramatch MOD2 .223 Wylde Barrel What firearm models does the manufacturer say Rainier Arms AR Ultramatch MOD2 .223 Wylde Barrel is compatible with? The manufacturer says that Rainier Arms AR Ultramatch MOD2 .223 Wylde Barrel is compatible with AR-15Rainier Arms Ultramatch MOD2 Barrel AR-15 .223 Wylde 18 in 1-7.5 Twist 1/2x28 Rifle Length Satin Silver RAB-UM2-223-18-R-FF-SAT