The Battle Arms Development AR-15 Workhorse 10.5 Upper M-Lok 1-7 Twist 5.56 NATO is a compact, ready-to-run upper receiver assembly built around a 10.5 inch Rosco 5.56 NATO barrel. A low-profile .750 gas block, free-float Workhorse 9.5 inch M-Lok rail, and A2 flash hider work together to keep the system smooth, controllable, and accessory-ready while maintaining a clean, streamlined profile.

This upper ships without a bolt carrier group or charging handle, letting you pair it with your preferred components and lower receiver. The forged 7075-T6 M4-style upper, nitride-finished 4150 CMV barrel, and carbine-length gas system make it well suited for range use, training, or a compact defensive build where reliability and maneuverability matter. Battle Arms Development’s attention to detail and proven engineering show through in the fit, finish, and thoughtful feature set of this Workhorse upper.

Key Features:

• Manufacturer: Battle Arms Development
• Model: Workhorse 10.5 Upper M-Lok 1-7 Twist 5.56 NATO
• Caliber: .223 Remington / 5.56 NATO
• Condition: New
• Barrel Length: 10.5"
• Threaded Barrel: Yes, 1/2x28 with A2 flash hider
• What's In The Box: Complete upper receiver assembly without BCG or charging handle
• Length: 18.5" overall upper length