The LBE Unlimited complete M16 bolt carrier group (brand part no. M16BCGNIB) is a fully assembled BCG chambered for 5.56x45mm NATO, built with an M16 full-auto carrier profile that many AR-15 owners run for its added mass and smoother cycling. The bolt is machined from 9310 tool steel and the carrier from 8620 steel, both finished in a nickel boron coating that reduces friction and simplifies cleaning compared to a standard phosphate finish. It ships complete with a staked gas key, firing pin, retaining pin, cam pin, extractor, and bolt gas rings, so it’s ready to drop into a mil-spec AR-15 upper.

Key Specifications

• Chambered for 5.56x45mm NATO.
• Bolt machined from 9310 tool steel for high strength and fatigue resistance.
• Carrier machined from 8620 steel for durability under repeated cycling.
• Finished in nickel boron (NiB) coating for reduced friction and easier cleaning.
• Built with the M16 full-auto carrier profile, favored by many AR-15 owners for its added mass.
• Gas key is staked for reliable, long-term function.
• Ships complete with a firing pin and retaining pin.
• Also includes a cam pin.
• Also includes an extractor and bolt gas rings.

Frequently Asked Questions

Is this BCG complete and ready to install? Yes, it includes the firing pin, retaining pin, cam pin, extractor, and bolt gas rings.

What caliber is this BCG built for? 5.56x45mm NATO.

Buy the LBE Unlimited Complete M16 Bolt Carrier Group

Upgrade your AR-15 with a complete, nickel-boron-coated BCG. Order it from our LBE Unlimited lineup, part of our AR bolt carrier groups selection, and have it ready to ship from our Lubbock, Texas gun shop.