Product DescriptionThe FN America AR-15 premium button rifled barrel is built to military specifications for dependable accuracy, long service life, and hard-use reliability. Manufactured from U.S.-sourced Chrome Moly Vanadium steel (Mil-B-11595E), each barrel is High Pressure Tested (HPT) and Magnetic Particle Inspected (MPI) to help ensure consistent quality and structural integrity. A chrome-lined bore and chamber improve corrosion resistance and reduce heat erosion for extended barrel life, while M4-style feed ramps support smooth, reliable feeding. Finished in a matte black manganese phosphate coating for external corrosion resistance, this 18-inch, rifle-length gas barrel is a strong choice for precision-focused AR-15 builds.Product Highlights 18-inch 5.56 NATO AR-15 barrel with rifle-length gas system for smooth cycling and controllable recoil impulse Chrome Moly Vanadium steel construction made to Mil-B-11595E standards for durability and performance Chrome-lined bore and chamber enhance corrosion resistance and extend barrel life HPT and MPI inspected to verify integrity and help eliminate micro-stresses or manufacturing flaws M4-style feed ramps and matte black manganese phosphate finish for reliable operation and corrosion protectionSpecs Brand: FN America Manufacturer Part Number: 20-100042 UPC: 845737008468 Caliber: 5.56 NATO Barrel Length: 18 in Gas System Length: Rifle-Length Barrel Contour/Profile: M16 Profile Rifling Method: Button rifled / button broached Twist Rate: 1:7 Bore & Chamber: Chrome-lined Material: Chrome Moly Vanadium steel Feed Ramps: M4 style Finish: Matte black manganese phosphate Testing: High Pressure Tested (HPT) and Magnetic Particle Inspected (MPI) Muzzle Threads: 1/2x28 Gas Block Journal Diameter: .750Disclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the products manufacturer.