Faxon Firearms Duty Series 5.56 NATO 16" Pencil Barrel Rifle - ML Nitride Finish

The Faxon Firearms Duty Series 5.56 NATO 16" pencil barrel is built for shooters who want a lightweight, durable AR-15 upper without compromising reliability. This 16-inch barrel features Faxon's signature slim profile—a narrow outside diameter both forward and behind the gas block—which strips unnecessary weight from your rifle while maintaining the structural integrity you need for hard use. Whether you're running a home-defense carbine, a competition setup, or a practical rifle for the range, this barrel pairs precision engineering with real-world durability.

Manufactured from 4150 CMV carbon steel at Faxon's ISO-certified facility, the barrel comes finished in ML Nitride for superior corrosion resistance and wear protection during extended shooting sessions. The 1-in-8-inch twist rate stabilizes the full spectrum of common 5.56 loads, from light varmint rounds to heavier service ammunition. M4 feedramps are cut into the barrel extension to ensure reliable feeding and extraction, and every barrel passes magnetic particle inspection to catch any material flaws before it ships.

This barrel accepts low-profile gas blocks (1 inch or shorter) with a .625-inch O.D. at the gas shoulder, and it's available configured for either carbine- or mid-length gas tube systems, so you can match it to your preferred dwell time and recoil impulse. The muzzle is threaded 1/2 x 28 for suppressors, flash hiders, or muzzle brakes. Note that the pencil profile will not accommodate standard-length front sight blocks, but pairs well with free-floating handguards and modern mounting solutions.

Faxon barrels are known for consistency and longevity—this Duty Series model is no exception. If you want a lightweight, no-frills barrel that handles real shooting without pretense, this is solid kit.

Key Features

• Pencil-profile design reduces weight without sacrificing strength
• 4150 CMV carbon steel with ML Nitride finish for durability and corrosion resistance
• 1-in-8-inch twist rate for stable flight across common 5.56 loadings
• M4 feedramps for reliable chambering and extraction
• Accepts low-profile gas blocks (.625" O.D., 1" or shorter)
• 1/2 x 28 threaded muzzle for accessories
• Available in carbine- or mid-length gas configurations
• Magnetic particle inspected for material consistency

Specifications

Frequently Asked Questions

What gas tube length does this barrel work with?

The Duty Series 16-inch pencil barrel is available configured for either carbine-length or mid-length gas systems. Choose the configuration that matches your intended build and intended dwell time.

Will this barrel work with my current gas block and handguard?

This barrel accepts low-profile gas blocks with a .625-inch O.D. that are 1 inch or shorter in length. It will not accept standard-length front sight blocks. The pencil profile pairs well with free-floating handguards and modern modular systems.

What twist rate is this barrel, and what ammunition does it stabilize?

The barrel features a 1-in-8-inch twist rate, which is fast enough to stabilize the full range of common 5.56 NATO loadings, from light varmint ammunition through heavier service rounds.

Can I attach a suppressor or flash hider?

Yes. The muzzle is threaded 1/2 x 28, the standard thread pitch for 5.56 NATO barrels, and will accept suppressors, flash hiders, muzzle brakes, and other 1/2 x 28 accessories.