... 1:AR15 Upper Receiver 2:Strictly tolerance control 3:100% inspection on critical dimension 4:Most reasonable production ... , blasting, painting, anodizing, heat treatment etc4: We have good cooperation companies, we make good use of outsourcing some factories and equipment ... upon request.16: IPQC inspect each during every step; 100% inspection before shipment by micrometer, height gauge, projector ...