Most companies regard their "TDP" or blueprint as confidential. Some companies, like FN, are forthcoming about barrel steel, but are tight lipped about the compounds used in the lower and stock.Yeah, this hush-hush attitude seems really juvenile. It's not like there will be a flood of aftermarket barrels made from a different material if this "proprietary info" somehow became public. Lemme guess, it's either 4140 or 4150 or something similar -- what's the big deal? It's not like it's pot metal....or is it???