Great Lakes Firearms and Ammunition AR-15 Bolt Carrier Group Features The Great Lakes Firearms and Ammunition AR-15 Bolt Carrier Group is machined from steel for the strength needed to cycle reliably under repeated firing cycles. Its black salt bath nitride finish provides excellent corrosion resistance while also reducing friction inside the upper receiver which helps the action cycle smoothly and resist fouling buildup. This finish is a popular upgrade over standard phosphate coatings because it holds up better to heat and wear over the life of the rifle. Compatibility across 5.56 NATO .223 Remington and .300 AAC Blackout chamberings means one carrier group serves a range of common AR-15 builds. Because the carrier is a direct fit for AR-15 pattern rifles it drops into a standard upper receiver without requiring custom fitting making it a practical option for a builder assembling a new upper or replacing a worn factory carrier. A properly finished correctly sized bolt carrier group is a foundational part of a reliable AR-15 since it directly affects how smoothly the action cycles and locks up. Choosing a steel carrier with a durable nitride finish gives a builder confidence the part will hold up to range use and field conditions alike. Great Lakes Firearms and Ammunition built this BCG as a dependable affordable option for AR-15 owners focused on reliability. Great Lakes Firearms and Ammunition AR-15 Bolt Carrier Group Specifications Manufacturer: Great Lakes Firearms and Ammunition Model: AR-15 Bolt Carrier Group Compatible Hosts: AR-15 5.56/.223/.300 AAC Blackout Material: Steel Finish: Black Salt Bath Nitride Caliber: 5.56 Available At: GrabAGun