This is one of the finest bolt carrier groups ("BCG") that you can put in your rifle. Weighing in at 11.4 ounces and in hard chrome, Young Manufacturing bolt carrier groups are synonymous with accuracy. With material in just the right places and precision brings, these BCGs will lock up tightly and consistently. My preferred method of mating this BCG to a new rifle is to coat the BCG with a thin coat of oil or grease and cycle the bolt manually 1,000 times. I'll break it up into 100 cycles per day for 10 days. This mates the BCG to the upper, barrel extension, and chamber in a controlled and well lubricated manner. Once this is done, I'll clean and re-lubricate the rifle and then push 200 rounds of slow controlled fire through it. When finished, clean and lubricate again...you're now ready for anything with a smooth firing and well lubricated rifle.
The National Match Bolt Carrier Group now comes with the HM Defense Bolt:
The HMB Bolt by HM Defense eliminates the pass through cam pin hole and replaces it with a cam pin socket and radiused cam pin design. The new patented design eliminates the natural weak point of Mil-Spec bolts by significantly increasing the amount of metal (and strength) at the cam pin location. The HMB Bolt also reduces contact between cam pin and firing pin, enabling smoother operation of firing pin, bolt lugs and aft gas rings. The new cam pin socket also retains lubrication for extended operations.