This is a stand out in the AR-15 world. Fit and function is perfect on my 8 inch barreled 7.62x39. Solid lock up on the barrel nut. Anodizing coverage is complete and is durable. I have not had any problems even with the added recoil of the .30 caliber pistol. Customer service is the best I have experienced. I have had great service from many companies and SLR always gets my #1 recommendation.