Designed using precision engineering adopted from the aerospace industry, Christensen Arms AR-15 carbon-fiber barrels are crafted using a proprietary layered design that offers any marksman superior accuracy and performance. The barrel lining is made from match-grade 416R stainless steel and is measured to a tolerance of +/- .0001. When it comes to accuracy, Christensen Arms carbon-fiber barrels have performance you can trust. Mfg: Christensen Arms