The FN America AR-15 Barrel (FN part number 20-100044) is a 14.70-inch, 5.56x45mm NATO barrel with a carbine-length gas system, manufactured from US-sourced Chrome Moly Vanadium steel to Mil-B-11595E specification. Each barrel is button rifled, High Pressure Tested, and Magnetic Particle Inspected to confirm it is free of microstresses or flaws, the same quality checks FN runs on barrels built for its own factory rifles. The bore and chamber are chrome lined to resist corrosion and heat erosion, extending barrel life and keeping chambering and extraction reliable, while M4-style feed ramps and barrel extension ensure consistent feeding. A matte black Manganese Phosphate finish resists external corrosion and oxidation.

Key Specifications

• Chambered in 5.56x45mm NATO (.223 Rem/5.56 NATO).
• Barrel length is 14.70 inches with a carbine-length gas system.
• Twist rate is 1 in 7 inches, right-hand.
• Rifling method is button rifling.
• Material is US-sourced Chrome Moly Vanadium steel, per Mil-B-11595E.
• Each barrel is High Pressure Tested (HPT) and Magnetic Particle Inspected (MPI).
• The bore and chamber are chrome lined for corrosion and heat resistance.
• Features M4-style feed ramps and barrel extension for reliable feeding.
• Finish is matte black Manganese Phosphate.

Frequently Asked Questions

Is this barrel tested for defects? Yes, every barrel is High Pressure Tested and Magnetic Particle Inspected to confirm it is free of microstresses or flaws.

Is the bore chrome lined? Yes, both the bore and chamber are chrome lined for corrosion and heat resistance.

What gas system length does this barrel use? It uses a carbine-length gas system at 14.70 inches.

Buy the FN AR-15 14.70 Inch Barrel

Build on a barrel that passes the same HPT and MPI quality checks FN runs on its own factory rifles. Browse more of our AR barrel selection and order from our Lubbock, Texas gun shop for fast, direct shipping.