CHROME-LINED PHOSPHATE FINISHED BCG: KAK Industry's rock-solid dependable 5.56 NATO bolt carrier group, chrome-lined and phosphate finished. The workhorse of our BCG portfolio, this product is made to provide years of unquestionable reliability without the sticker shock. FULL CHROME BCG: Full Chrome. Hard Chrome. Machine Gun Chrome. Regardless of what you call it, this BCG is as tough as it is good looking. KAK Industry's 5.56 NATO Full Chrome BCG is made for unflinching reliability no matter how rough the use. All KAK Industry BCGs feature a M16 (Full Auto) carrier profile, meticulously machined from 8620 steel, properly heat treated and ground to exact tolerances. Mfg: Kak Industry Llc.