NLX 308 Left Hand Bolt Carrier Group The NLX 308 Left Hand Bolt Carrier Group provides improved function and operation via several key improvements. The expanded rear of the carrier allows for smooth cycling in the buffer tube. The team at Next Level Armament will apply coating to all internal parts, including the firing pin, cam pin and extractor. Assembled with hardened Grade 8 gas key screws, we then properly torque & stake each gas key. We shot peen and MPI inspect each bolt. Our NLX 308 Left Hand Carrier is machined from 4140ph steel to aerospace tolerances. Whether you hunt, shoot for accuracy, or just plink on the range, our 308 Left Hand Bolt Carrier group will give you long lasting dependable service. Combine the BCG with our 308 left hand upper for a complete set and experience the quality Next Level delivers. DLC Finish The DLC coating gives excellent protection against abrasion, tribo-oxidation and adhesion (scuffing). The coating permits surface pressures that, under normal conditions, would lead at once to scuffing and cold welding. This reduces friction losses to a minimum. The good corrosion resistance protects the substrate from destructive attack. The Rockwell hardness on the outside is double a Phosphate BCG.