Available for Order Today, 6mm ARC Complete Upper Receiver Groups from Aero Precision Brownells partnered with Aero Precision and Ballistic Advantage to bring Upper Receivers in the exciting new 6mm ARC to market. Each Aero Precision 6mm ARC Complete Upper Receiver features a M4E1 Receiver with Atlas R-One 15 Inch Handgaurd. Each Stainless Steel Barrel is precision machined by Ballistic Advantage, with a 1-7 twist and a bead blast finish, and in the case of the 18 inch model an optional black nitride finish. 16" and 18" upper offer a mid-length gas system and the longer 20" and 24" setups have a rifle length gas system. Uppers include a Mfg: Aero Precision
