The Faxon Firearms Duty Series Barrel in 5.56x45mm NATO, 16 inches, QPQ black nitride finish (brand part no. 15A58M16NPQ) is machined from 4150 mil-spec steel for AR15/M16-pattern rifles that need long service life over exotic materials. Faxon button-rifles the bore and cuts it in a Pencil profile with a mid-length gas system, then puts every barrel through a battery of tests at each manufacturing step before final Nitride finishing and inspection. Headspace is checked individually with precision, custom-hardened gauges before the barrel ships. At a full 16 inches, it is a compliant rifle-length barrel ready to drop into a standard AR15 or M16-pattern upper.

Key Specifications

• Chambered in 5.56x45mm NATO / .223 Remington.
• Barrel length measures 16 inches.
• Rifling uses a 1:8 twist rate with button rifling.
• Machined from 4150 mil-spec steel.
• Cut in a Pencil profile for reduced weight.
• Runs a mid-length gas system.
• Finished in Nitride, both inside and out.
• Threaded 1/2-28 at the muzzle.
• Given an 11-degree target crown and a 1.1-inch gas block journal.
• Ships without sights.

Frequently Asked Questions

What gas system does this barrel use? A mid-length gas system with a 1.1-inch gas block journal.

What material is the barrel made from? 4150 mil-spec steel, individually headspace-checked with custom-hardened gauges.

Does the barrel include sights? No, it ships without sights.

Buy the Faxon Firearms Duty Series Barrel

Build a full-length, mil-spec 5.56 AR15 upper around a durable, individually tested barrel. Browse more Faxon Firearms parts in our AR15 barrels selection and order direct from our Lubbock, Texas gun shop for fast shipping to your door.