The FN America 18-inch AR-15 Barrel (brand part no. 20100042) is a button-rifled, government profile barrel chambered in 5.56 NATO/.223 Remington. FN builds this barrel with a rifle-length gas system and a 1 in 7 inch right-hand twist rate suited to a wide range of 5.56 bullet weights, along with M4 feed ramps for reliable feeding on flat-top AR-15 uppers. The barrel ships threaded and finished in black, ready for a muzzle device of your choosing. Coming from FN America / FN Herstal, a manufacturer known for supplying barrels to military and law enforcement contracts, this 18-inch length is a popular choice for shooters who want a rifle-length gas system without stepping up to a full 20-inch barrel.

Key Specifications

• Chambered in 5.56 NATO/.223 Remington.
• Barrel length measures 18 inches.
• Rifled with a 1 in 7 inch right-hand twist for a wide range of bullet weights.
• Uses a rifle-length gas system.
• Machined with a government profile contour.
• Finished in black.
• Rifling is button rifled for consistent bore dimensions.
• Includes M4 feed ramps for reliable feeding on flat-top uppers.
• Barrel is threaded at the muzzle for a compensator or flash hider.
• Does not include iron sights.

Frequently Asked Questions

What gas system length does this barrel use? It uses a rifle-length gas system, which is common on 18 to 20-inch 5.56 AR-15 builds.

Does this barrel come threaded? Yes, the muzzle is threaded so you can install your muzzle device of choice.

Does it include sights? No, this is a bare barrel with no iron sights included.

Buy the FN America 18-inch AR-15 Barrel – 1:7 Rifle Gas, Government Profile

Order this FN America 18-inch AR-15 barrel from FN America / FN Herstal through our AR barrels lineup, shipped fast from our Lubbock, Texas gun shop.