The Faxon Duty Series Barrel for the 5.56x45mm is manufactured 100% in-house from cradle-to-grave. The barrel is machined from certified 4150 GBQ steel with QPQ nitride coating for added durability and longevity. Each barrel is magnetic particle inspected (MPI) to ensure perfect surfaces and sub-surfaces as well as air-gauge tested to ensure superior accuracy. The Faxon Pencil contour barrels are button rifled, and the lightest in the industry and are ideally balanced for performance. With Faxon's Integral Muzzle Device Barrels customers will no longer be locked into a single configuration on their rifle build or be dependent on finding a capable gunsmith to pin & weld their muzzle device to their barrel. The integral muzzle device allows the full assembly and disassembly of barrel and barrel nuts. Shooters are forever free to change their weapon's configuration. The Gunner profile is a blend of two of the best performing profiles of all time, Gov't and Pencil. Faxon's Gunner profil...