FN AR-15 5.56x45mm NATO 14.7" M4 Profile Barrel

The FN AR-15 14.7" M4 Profile Barrel is a replacement barrel for AR-15-pattern builds chambered in 5.56x45mm NATO. Its chamber also accommodates .223 Remington ammunition.

Built with a 14.7 in M4 profile and a carbine-length gas system, this barrel uses a 1:7 twist. An M4-style barrel extension and feed ramps complete the AR-15-focused configuration.

FN cold-hammer forges the barrel from proprietary high-grade chrome-moly-vanadium steel. The bore and chamber are chrome-lined to resist corrosion, heat erosion, and wear while supporting reliable chambering and extraction.

A matte black manganese-phosphate finish provides external resistance to corrosion and oxidation. Each barrel is magnetic-particle tested after forging to identify microscopic stresses or flaws.