FN AR-15 18″ M16 Profile Rifle-Length Barrel, 5.56 NATO

Designed for AR-15 platform rifle builds, this FN America / FN Herstal 18-inch M16 profile barrel is intended for rifle-length gas system configurations where consistent feeding and extended barrel life are priorities. The barrel is manufactured from U.S.-sourced Chrome Moly Vanadium material to Mil-B-11595E standards and is button rifled for consistent bore dimensions. Each barrel receives High Pressure Testing (HPT) and Magnetic Particle Inspection (MPI) to check for micro-stresses and flaws. The bore and chamber are chrome lined, and the exterior receives a matte black manganese phosphate finish for corrosion resistance.

Key Specifications

• The caliber is 5.56x45mm NATO (.223 Rem).
• The barrel length is 18 inches.
• The rate of twist is 1 in 7″ right-hand.
• The contour/profile is Government (M16) profile.
• The gas system length is Rifle length.
• The rifling method is button rifled.
• The bore and chamber are chrome lined.
• The exterior finish is matte black manganese phosphate.
• The muzzle threads use 1/2-28 pattern.
• The barrel features M4-style feed ramps and a barrel extension for consistent feeding.

This barrel brings factory-level inspection and protective finishes to AR-15 rifle-length builds, combining durable materials, chrome lining, and a duty-style profile for reliable performance in field and precision-oriented applications. Its M4 feed ramps and M16 contour make it a straightforward upgrade for builds that require consistent feeding and extended barrel life.