Spike's Tactical NiB Light Weight .223/5.56 Bolt Carrier Group. This BCG has been High Pressure Tested, Magnetic Particle inspected and dimple milled to save on weight! Nickel Boron has proven itself to be the most durable finish on the market. It’s much smoother than Hard Chrome, it’s easier to clean, makes the rifle cycle smoother, it can be run almost lube free for thousands of rounds, and it will never chip, peal, or flake off! Approximately 10.4 ounces.