These have cosmetic finish blemishes and/or machining blemishes- rough machining marks, it will not affect function, price reduced.KAK Industry Complete Chrome Bolt (Heavy Chrome/ Machine Gun Chrome) Complete Assembled Bolt OnlyBolt- 9310 steel, outside diameters ground to .0002 tolerances, MPI test, Heavy Chrome Finish (Machine Gun Chrome)Extractor- 4140 steel, fully machined, Phosphate coatedExtractor pin- S7 tool steel, ground, heat treatedEjector- S7 tool steel, ground, heat treated1.44 ozMachined in house and assembled using only the finest steels and components. KAK Industry takes pride in producing some of the finest Mil-Spec/ Enhanced AR15 bolts available, made 100% in house at our MO facility using Doosan machining centers, Tsugami Swiss turning, and the latest in FANUC robotics combined into an automated cell giving us lights out production capability. In house automated CMM Inspection processes ensure consistent quality.