FN 20-100041 AR-155.56x45mm NATO 16" Button Rifled M16 Profile Mid Length Gas System, Black Phosphate Cold Hammer Forged Chrome Lined

The FN AR-15 5.56x45mm NATO 16" barrel is a cold hammer-forged upgrade for shooters who demand mil-spec reliability without compromise. Built from U.S.-sourced Chrome Moly Vanadium steel and finished in black phosphate, this mid-length gas system barrel combines rugged durability with the kind of precision fit that matters whether you're running a duty rifle, competition build, or dependable hunting platform. FN's manufacturing process—including high pressure testing and magnetic particle inspection at the factory—means you're getting a barrel that's been vetted for hidden stress and defects before it ships.

The chrome-lined bore and chamber are engineered to handle sustained fire and rough conditions. That lining resists corrosion and heat erosion, stretching barrel life and keeping extraction smooth even after thousands of rounds. The M4-style feed ramps on the barrel extension ensure consistent feeding, so you can trust your ammunition to chamber reliably shot after shot. The 16" length and mid-length gas system strike a practical balance—short enough for maneuverability in a carbine, long enough to wring real velocity from 5.56 loads without the extra blast of a shorty.

If you're rebuilding an AR or swapping a worn barrel, this FN replacement meets military specifications (Mil-B-11595E) and works with standard AR-15 upper assemblies. The matte black finish resists external corrosion and oxidation, holding up to field use and storage. It's the kind of barrel that works quietly in the background—no marketing hype, just consistent function that you can count on.

Key Features

• Cold hammer-forged construction from U.S.-sourced Chrome Moly Vanadium steel
• Chrome-lined bore and chamber for extended barrel life and corrosion resistance
• 16" length with mid-length gas system—balanced for carbines and standard ARs
• M4-style feed ramps for reliable feeding
• Black phosphate finish resists corrosion and external wear
• Factory high pressure tested (HPT) and magnetic particle inspected (MPI)
• Mil-B-11595E specification compliance

Specifications

Frequently Asked Questions

Will this FN barrel work with my standard AR-15 upper receiver?

Yes. This is a standard AR-15 barrel assembly designed to drop into any mil-spec AR-15 upper receiver. The M4-style feed ramps and barrel extension ensure compatibility with typical AR platforms.

Why is the chrome-lined chamber important?

The chrome lining protects the chamber from heat erosion and corrosion, which means better reliability when firing and extracting ammunition, plus a longer useful barrel life. This is especially valuable if you shoot in high-round-count sessions or store your rifle in less-than-ideal conditions.

What does "cold hammer-forged" mean, and why does it matter?

Cold hammer forging compresses the steel at room temperature into a barrel blank, creating a denser, more uniform structure than other methods. The result is a stronger barrel with fewer hidden defects—which is why FN backs it up with high pressure testing and magnetic particle inspection before it leaves the factory.

Is this barrel suitable for hunting and field use?

Yes. The 16" length and mid-length gas system provide a good balance of velocity and handling for a modern carbine. The black phosphate finish and chrome lining offer the durability you need for hunting and outdoor use.