Fostech

This is a standard full-auto M16 cut bolt carrier group. It is designed to function with the Echo AR-II and the Echo Sport. Bolt Assembly - Bolt: Shot Peened; Magnetic Particle Inspected and Marked - Bolt Material: 9310 Alloy Steel - Compatibility: .223 / 556 / 300BLK - Extractor: Shot Peened Hardened Tool Steel - Extractor O-Ring: Viton Mil-Spec - Gas Rings (3): Mil-Spec - Finish: BLACK NITRIDEBolt Carrier - Material: 8620 Steel - Design: Heavy Profile M16 Style - (Preferred for most AR-15 Builds) - Gas Key Screws: Grade 8; Properly Torqued and Staked to Mil-Spec - Gas Key Material: 4130 Steel - Finish: BLACK NITRIDECam Pin - Material: 4140 Steel - Finish: BLACK NITRIDEFiring Pin - Material: 8740 Steel; Centerless Ground; Hard Chrome Plated - Weight: 11.6 Ounces100% USA Made