Proof Research Barrel's are a high quality barrels which are made to extremely high quality standards. The design and manufacturing processes which are used are state of the art and go above and beyond. Each barrel produced will exemplify their founders relentless pursuit of excellence. The ultimate goal of proof research is to provide you with the performance and quality you have been missing whether it's to shoot your best groups, compete at the highest levels, or bag that elusive animal. Whatever your choice of shooting discipline proof research has the finest barrels in the firearms industry.Proof Research PR15 AR Style Barrel Specifications and Features: Proof Research 130438 Carbon Fiber AR Style Barrel 6 ARC 20" Barrel 1:7.5" Twist Rate Threaded 5/8x24 Rifle +1 Length Gas System Length .750" Gas Journal Diameter .416R Stainless Steel/Carbon Fiber Overall Weight 2lbs 3oz Up to 64% lighter than traditional steel barrels of similar contour Match-Grade Accuracy Improved Heat Dissipation for cooler and longer lasting barrels No point of impact shift during high volume fire Reduced Harmonic Barrel Vibration Unprecedented Durability