The One Horse 18" 6mm ARC Rifle 1:7.5 M-LOK Complete Upper transforms a standard AR-15 lower into a precise, flat-shooting platform. Built around an 18-inch 416R stainless steel barrel with a 1:7.5 twist and 5/8x24 threaded muzzle, this upper is paired with a free-float M-LOK handguard and a nitride-finished bolt carrier group for smooth, reliable operation.

This complete upper is ideal for long-range target shooting, varmint hunting, and general range use where consistent accuracy and manageable recoil matter. The rifle-length gas system promotes softer cycling and better control over extended sessions, while the included charging handle and BCG make installation straightforward on any Mil-Spec AR-15 lower. One Horse’s attention to detail and solid craftsmanship result in a dependable upper that maximizes the performance of the 6mm ARC cartridge.

Key Features:

• Manufacturer: One Horse
• Model: 18" 6mm ARC Rifle 1:7.5 M-LOK Complete Upper (OH-CU09)
• Caliber: 6mm ARC
• Barrel Length: 18 inches
• Twist Rate: 1:7.5
• Muzzle Thread: 5/8x24
• Gas System Length: Rifle
• Handguard: Free-Float M-LOK
• BCG / Charging Handle: Included