We offer a wide variety of Bolt Carrier Groups for your AR-15 Build. We have all caliber variety of Bolt Carrier Groups such as 5.56, .223, .308, 7.62×51, 7.62×39, 6.5 Grendel, 6.5 Creedmoor and 9mm. All of our AR-15 Bolt Carrier Groups, also known as BCG’s, are Nitrided in 9310 Steel. 9310 Steel is only about 8% stronger, but when you combo it with shot peened and QPQ (Nitrided), you have a better BCG that will last longer and easier to clean. You can’t find a better selection of AR-15 Bolt Carrier Groups that have great discounts. We are your experts when it comes to all things AR-15, AR-308, AR 9mm, AK-47 and Sig MPX.