Trust only T6-7075 forgings for your AR rifles. At UDMC, we can issue a written certification that your receivers are made of the highest quality ordnance and aerospace grade T6-7075 forgings. Be forewarned that receivers milled from castings, billets and blankings are not T6-7075 aluminum forgings and are less than HALF the strength and durability of the real MILSPECS receivers that is the standard in making any type of AR rifle. To be sure, ask your supplier for a written certification of the origin of the receivers and when in doubt, have it analyzed for chemical composition and mechanical properties at the Metals Industry Research and Development Center of the DOST.