The Rosco Manufacturing K9 11.5'' Patrol Length Barrel in 5.56 NATO is engineered for AR-15 platforms, delivering a continuous contour with a nitride finish that pairs durability with corrosion resistance. This 11.5-inch barrel features a 1-7 twist and 1/2-28 muzzle threads, optimized for reliable stabilization of commonly used 5.56 ammunition and versatile handling in patrol or dynamic field scenarios. Weighing approximately 1.25 pounds, its patrol-length gas system balances reduces felt recoil with smooth cycling, contributing to steady follow-up shots and sustained accuracy in rapid-fire contexts. Designed to integrate seamlessly with AR-15 builds, this barrel brings robust performance to rifle parts and rifle barrels that demand consistent dimensional fit and proven hard-use reliability. Its nitride treatment enhances wear resistance while maintaining a precise bore, helping maintain accuracy across extended shooting sessions. With Rosco Manufacturings attention to detail, the K9 11.5'' barrel is well-suited for duty-grade configurations, sport shooting, and professional applications where dependable ballistic performance and a streamlined profile matter most.