K-SPEC: Mil-Spec, Enhanced. KAK Industry's signature design for unrivaled performance and unparalleled reliability, all K-SPEC Enhanced BCGs retain mil-spec dimensions with added Slotted Angle Carrier Rails ("sand cutters") and Dual Ejector system. All KAK Industry BCGs feature a M16 (Full Auto) carrier profile, meticulously machined from 8620 steel, properly heat treated and ground to exact tolerances. Other components include: Single piece billet-machined 4140 extractor, phosphate coated for Increased reliability and corrosion resistance. Includes 4340 Chrome plated cam pin. 8740 chrome plated firing pin, precision ground and heat trea Mfg: Kak Industry Llc.