The FN AR-15 Barrel (brand part number 20100047) is a 16-inch, M4-profile barrel chambered in 5.56x45mm NATO and built with a carbine-length gas system for standard AR-15 configurations. FN hammer-forges the barrel using the same proprietary high-grade chrome-moly-vanadium steel the company uses in its machine gun barrels built to handle sustained full-automatic fire, then Magnetic Particle tests every barrel to confirm it’s free of microstresses or flaws before it ships. The bore and chamber are chrome-lined for corrosion resistance and heat-erosion protection, which extends barrel life and keeps chambering and extraction reliable, and the M4-style feed ramps and barrel extension improve feeding consistency. A matte black manganese phosphate finish resists external corrosion and oxidation.

Key Specifications

• Chambered in 5.56x45mm NATO.
• Measures 16 inches in a M4 profile with a carbine-length gas system.
• Cut with a 1:7 twist rate.
• Cold hammer forged from chrome-moly-vanadium steel.
• Bore and chamber are chrome-lined for corrosion and heat-erosion resistance.
• Built with M4-style feed ramps and barrel extension for reliable feeding.
• Finished in matte black manganese phosphate.
• Every barrel is Magnetic Particle tested for defects.

Frequently Asked Questions

Is this barrel chrome-lined? Yes, the bore and chamber are chrome-lined for corrosion resistance and extended barrel life.

What gas system does this barrel use? A carbine-length gas system, matched to the M4 profile.

Buy the FN 16-Inch AR-15 Barrel

Build with the same forging process FN uses on its machine gun barrels. Order this barrel from our FN America lineup of AR barrels for fast, reliable shipping from our Lubbock, Texas gun shop.