Faxon starts with 4150 Mil-Spec steel from there, each barrel goes through a battery of tests at each operation until finished in Nitride and final inspected. All barrels are individually checked for headspace by precision custom hardened gauges. Features button rifling; Pencil profile; mid barrel gas system; Nitride inside and outside finish; 1/2"-28 thread; 11 degree target crowned; 1.1" gas block journal and M4 barrel extension.