One Horse 16 5.56 Complete Upper Features The One Horse complete upper is chambered in 5.56 NATO and built around a 16 barrel giving builders a ready-to-run carbine configuration without sourcing and assembling individual upper components. Because it ships as a complete assembly it saves the time and tooling that fitting a barrel gas block and bolt carrier group individually would otherwise require. The 16 barrel length keeps the completed rifle within standard non-NFA specifications while still delivering the velocity carbine-length 5.56 ammunition is designed around. A flat-top upper receiver gives the completed rifle a standard Picatinny rail for mounting optics once installed on a lower. Pairing this upper with any mil-spec AR-15 lower receiver completes a functioning rifle without further machining or fitting work. This makes the One Horse upper a practical option for builders assembling a second rifle from spare lowers or replacing a worn or damaged upper on an existing build. Its carbine-length configuration keeps handling familiar to anyone who has run a standard AR-15 pattern rifle. For an AR-15 builder wanting a straightforward complete 16 5.56 upper the One Horse assembly delivers exactly that. One Horse 16 5.56 Complete Upper Specifications Manufacturer: One Horse Type: Complete Upper Caliber: 5.56 Barrel Length: 16 Compatible Hosts: AR-15 Available At: GrabAGun