A good Bolt Carrier Group is one of the most important parts of your gun. If it malfunctions, you are dead in the water. These are precision pieces manufactured to the strictest of tolerances. It might be your life that depends on your weapon or just your pride. Make sure you leave the house with the pieces that will get you home again. The Samson Armory offers complete AR-15 (BCGs) Bolt Carrier Groups, carriers, bolt assemblies, and misc. small parts.