DealBlack Dirt Rifleworks Stripped AR15 Upper Receivers are precision machined from certified 7075-T6 aluminum forgings and feature a special burnished bore that gives a compacted internal surface, resulting in a much smoother surface finish and greatly reduces bolt carrier friction resulting in a much smoother operation and increased reliability. The barrel nut threads, bore and barrel extension surfaces are all machined in one operation so that they are perfectly concentric and perpendicular to the barrel and fixing assembly. from Ground Zero Precision (Product BDR-MS15UP-STA) |