With its more than 100-year legacy of exceptional barrel manufacturing FNH USA has long since perfected the cold hammer forging process to ensure accuracy and durability. FN AR-15 barrels are hammer forged using the same proprietary high-grade Chrome Moly Venadium steel used in FN’s venerable machinegun barrels produced to handle the punishment of sustained fully-automatic fire. After forging each barrel is Magnetic Particle tested to ensure that it is free of micro-stresses or flaws resulting in consistency and quality in every barrel shipped from the factory. The bore and chamber are chrome lined to help resist corrosion and provide resistance to heat erosion which greatly improves barrel life and reliable chambering/extraction. The M4 style feed ramps and barrel extension provide consistent feeding and the matte black Manganese Phosphate finish resists external corrosion and oxidation. Currently available in a chambering of 5.56x45mm.