One Horse Complete AR-15 Upper Receiver - 300 Blackout - 10.5"

Overview

The One Horse Complete AR-15 Upper Receiver in 300 Blackout features a 10.5-inch medium-profile 4150 steel barrel with a nitride treatment, a 5/8x24 threaded muzzle, a pistol-length gas system, and a nitride bolt carrier group along with a standard charging handle. The 4150 steel barrel offers improved wear resistance at the bore and chamber compared to entry-level 4140 variants, while the nitride treatment provides a hard, corrosion-resistant surface. Built to mil-spec standards in the USA, the upper includes a 10-inch M-LOK free-float handguard secured with a steel barrel nut for a rigid connection under repeated thermal cycling. Because the barrel measures under 16 inches, this complete upper is intended for use on an AR pistol or a legally registered short-barreled rifle.

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