Bolt carrier group for your AR15 or M16 (full auto). Manufactured and assembled by USGI Contractor DSArms. Completely assembled, includes bolt carrier, bolt, firing pin, cam pin, and retaining pin. 

Bolt

9310 Super Alloy Steel (7% stronger than Carpenter No. 158® Steel)
MPI Bolt (Magnetic Particle Inspected)
Hardened Steel Extractor
Heavy Duty Extractor Spring
Black Extractor Insert
Mil-Spec O-Ring
Milspec Gas rings (3)
Parkerized exterior

Bolt Carrier

Proper 8620 steel
Shot Peened
Chrome Lined Carrier
Properly Staked Chrome lined Gas Key
Grade 8 Gas Key Screws
Heavy Duty M16 design
Parkerized exterior

Cam Pin Hardened Steel Parkerized exterior 

Firing Pin Hardened Steel Chrome Plated 

Firing Pin Retaining Pin Hardened Steel Black Oxide Exterior