One Horse OH-15 Complete Upper Features The One Horse OH-15 Complete Upper is built around a 7.5-inch 4150 steel medium profile barrel with a 1:7 twist rate delivering the heat resistance durability and dimensional consistency that 4150 steel is known for in the most demanding compact and suppressed AR-15 pistol applications. A pistol-length gas system is specifically optimized for reliable and consistent cycling with .300 Blackout ammunition across both supersonic and subsonic load profiles at this ultra-compact barrel length making this upper an outstanding foundation for a dedicated suppressed .300 Blackout pistol build. The 5/8x24 threaded muzzle accepts a wide range of aftermarket muzzle devices and suppressors keeping the upper fully suppressor-ready to take full advantage of .300 Blackout s exceptional subsonic performance. The 7-inch handguard provides a free-float platform that eliminates barrel contact for maximum accuracy potential while delivering a stable gripping surface in the most compact and maneuverable form factor possible for an AR-platform pistol. A standard charging handle provides a familiar and intuitive operating experience for any shooter already comfortable with the AR-15 platform. The 7.5-inch barrel and 7-inch handguard combination delivers the most compact and close-quarters-ready profile in the OH-15 Complete Upper lineup purpose-built for vehicle carry home defense and suppressed shooting applications where every inch of overall length matters. Designed for AR-15 pistol builders and .300 Blackout enthusiasts who want the most compact and suppressor-optimized complete upper available without the complexity of individual component sourcing the One Horse OH-15 Complete Upper delivers exceptional performance in an ultra-compact package. The medium barrel profile and pistol-length gas system pairing at 7.5 inches represents one of the most capable and purpose-built configurations for dedicated suppressed .300 Blackout pistol builds on the market today. For builders who demand the ultimate in compact .300 Blackout pistol upper performance the OH-15 Complete Upper is the definitive choice. One Horse OH-15 Complete Upper Specifications Manufacturer: One Horse Model: OH-15 Complete Upper Caliber: .300 Blackout Barrel Length: 7.5 Barrel Profile: Medium Barrel Material: 4150 Steel Twist Rate: 1:7 Gas System: Pistol Muzzle Thread: 5/8x24 Charging Handle: Standard Handguard Length: 7