The One Horse OH-CU04 16" 300 Blackout Complete Upper Receiver brings together a 16-inch 4150 steel SOCOM-profile barrel, a 15-inch free-float M-LOK handguard, and a nitride bolt carrier group and charging handle in one ready-to-install package. The pistol-length gas system, 5/8x24 threaded muzzle, and included A2-style muzzle device create a smooth-shooting upper that pairs easily with a compatible AR-15 lower.

This upper is well suited for shooters who want a dedicated 300 Blackout build for range use, training, or hunting where the longer barrel and extended handguard provide stability and ample accessory mounting space. With its full-length top rail and clamp-on handguard design, the OH-CU04 offers a solid foundation for optics and accessories while reflecting One Horse’s focus on practical performance and straightforward craftsmanship.

• Manufacturer: One Horse
• Model: OH-CU04
• Caliber: 300 Blackout
• Barrel Length: 16"
• Barrel Profile: Socom
• Barrel Material: 4150 Steel
• Rate Of Twist: 1:7
• Thread Pattern: 5/8x24
• Muzzle Device: A2-Style
• Handguard: 15" M-Lok Free-Float
• Bolt Carrier Group: Nitride
• Charging Handle: Included
• Platform: AR-15