VKTR Industries Bolt Carrier Group DI Complete 9310 Nitride Bolt ID OD Thin Dense Chrome Carrier. The patented enhanced cam pin provides consistent lock up reducing headspace variations. Match grade performance right out of the box and a true drop-in component that will work with any barrel and gas system length. Specifications for VKTR Industries DI Complete Bolt Carrier Group: Manufacturer: VKTR Industries Color: One Color Fabric/Material: Heat Treated 8620 Alloy Steel Caliber: 5.56mm Features of VKTR Industries DI Complete Bolt Carrier Group CNC Precision Machined Heat Treated 8620 Alloy Steel Patented Long Advance Cam Path Faceted Carrier Design Full-Auto Rated Grade 8 Gas Key Screws Thin Dense Chrome Plated Lifetime Warranty Package Contents: VKTR Industries DI Complete Bolt Carrier Group VKTR Industries V-2009-0719-002-RP: Bolt Carrier Group DI Complete 9310 Nitride Bolt ID OD Thin Dense Chrome Carrier