FN 20-100044 AR-15 5.56x45mm NATO 14.70" Button Rifled M4 Profile Carbine Length Gas System, Black Phosphate Cold Hammer Forged Chrome Lined 20100044

The fighting rifle trusted by U.S. troops today is the M4A1 carbine, and at the core of this light, compact rifle is a battle-proven barrel design made right here in the USA by FN America. Now, you can get your own barrel made by the same factory and enhance your stock AR-15 or build your perfect M4 clone. This is the BB M4 barrel from FN America.

After button-rifling, each FN AR-15 BB M4 barrel gets a chrome-lined bore and chamber that prevents corrosion and also minimizes heat erosion. This helps to extend the life of your rifle, as well as enhance reliability. After chrome-lining, each barrel is high-pressure tested and MPI-inspected to ensure it meets all military standards. Outside, the barrels are treated with a manganese-phosphate finish that resists corrosion.

These FN AR-15 BB M4 barrels are all chambered in 5.56 NATO and are available in the following barrel and gas-system lengths: 14.7-inch with a government profile and a carbine gas system, and 16-inch with a government profile and carbine gas system.