KAK Industry's rock-solid dependable .224 Valkyrie / 6.8 SPC bolt carrier group, chrome-lined and phosphate finished. The workhorse of KAK Industry's BCG portfolio, this product is made to provide years of unquestionable reliability without the sticker shock. 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. 4340 phosphate coated cam pin. 8740 chrome plated firing pin, precision ground and heat treated. Mfg: Kak Industry Llc.