Azimuth Technology is one of the premier BCG makers in the industry. Made in USA with premium materials. Carrier Specifications Material: 8620 Steel Type: M16 Full Auto (Preferred for most AR-15 builds) Grade 8 Gas Key Screws Coating: Black Nitride Bolt Specifications Bolt Material: 9310 Steel | Shot Peened Extractor Material: 4140 Steel Caliber: 6.5 Grendel (Type II) Mil-Spec O-Ring Mil-Spec Gas Rings (3) Cam Pin Material: 8620 Steel Firing Pin Material: 416 Stainless Steel Other: MPI Inspected Lifetime Warranty - Azimuth BCGs carry a lifetime, no questions asked, warranty.