We strive for the BEST BCG on the market for the BEST price. We use 9310 steel bolts and Carriers that far exceed mil-spec. Why you ask, because when military standards were made, they used .223 rounds, with carpenter 158 steel. When high pressure 5.56 NATO because the standard, they did not change standard military spec. 9310 steel is only about 8% stronger, but when you combo it with shot peened and QPQ (nitrided), you have a better bolt that will last longer and easier to clean! Remember we ship same or next business day!