Fully assembled and ready to drop in. M16 carrier with a Nickel Boron coating. Bolt is made of Carpenter 158 steel. BCG will work with these calibers: 5.56, 223, and 300BLK. Lifetime ToolCraft Warranty! Made in USA.
Bolt Carriers are made from 8620 Aircraft Quality Steel
Gas Keys are made from 4130 Steel
Bolts are made from 9310 Steel
Includes Crane type o-ring
All Toolcraft products carry a lifetime, no questions asked, warranty.