.300 BLK

Duty Series .300 Blackout AR-15 Barrels

Faxon Firearms Duty Series .300 Blackout AR-15 barrels are engineered for shooters who demand reliability, durability, and consistent performance in real-world use. Designed and manufactured entirely in-house in Greater Cincinnati, Ohio, these barrels are built from 4150 CMV steel and optimized for both suppressed and unsuppressed .300 BLK applications.

The .300 Blackout cartridge places unique demands on a barrel—wide bullet weight ranges, fast twist requirements, and reliable cycling across subsonic and supersonic loads. Faxon Duty Series barrels address these challenges through proven materials, conservative gas system tuning, and strict quality control. Each barrel is stress relieved, precision machined, and 100% wet MPI inspected before leaving our facility.

Duty Series .300 Blackout Barrel Features

  • 4150 CMV steel for superior heat resistance and durability
  • Button-rifled bore with traditional rifling for reliability across ammo types
  • Salt bath nitride finish for corrosion resistance and extended barrel life
  • 11-degree target crown for consistent gas release
  • M4 feed ramps for reliable feeding
  • 100% in-house stress relief and wet Magnetic Particle Inspection (MPI)
  • Manufactured entirely in the USA in Greater Cincinnati, Ohio

Built for Suppressed and Unsuppressed .300 BLK Use

.300 Blackout spans a wide range of loads—from lightweight supersonics to heavy subsonics commonly paired with suppressors. Faxon Duty Series .300 BLK barrels are tuned for practical reliability across both use cases, with durable 4150 CMV construction that resists throat erosion and heat-related wear in high-round-count shooting.

Duty vs Match vs AXIS: Which Faxon Barrel Series Should You Choose?

Choosing the right barrel series depends on how you use your rifle. All Faxon barrels are manufactured in-house in Greater Cincinnati, Ohio with strict inspection standards, but each series is optimized for a different priority.

  • Duty Series — Built for hard use and longevity. 4150 CMV steel with traditional rifling and salt bath nitride protection. Ideal for duty rifles, training volume, and shooters who prioritize durability and reliability.
  • Match Series — Built for maximum precision potential. 416R stainless steel with 5R rifling and a recessed 11-degree crown to help protect the bore edge. Ideal for shooters chasing tight groups with higher-quality ammunition and precision-focused builds.
  • AXIS Series — Built for shooters who want premium performance in a simplified, purpose-driven configuration. AXIS barrels are engineered to deliver Faxon quality and practical accuracy with modern cartridge support and feature sets that emphasize value and application-fit.

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Are Duty Series .300 Blackout barrels a good choice for suppressed builds? ▾

Yes. Duty Series .300 BLK barrels are designed for reliable function across suppressed and unsuppressed use, including common subsonic and supersonic ammunition types.

What is the difference between .300 BLK and 5.56 barrels? ▾

.300 Blackout barrels use a different bore diameter and chamber to support .30 caliber projectiles and are designed to run both subsonic and supersonic loads. A 5.56 barrel cannot safely fire .300 BLK ammunition.

What steel is used in Faxon Duty Series barrels? ▾

Faxon Duty Series barrels are made from 4150 CMV (Chromium-Molybdenum-Vanadium) steel for strength, heat tolerance, and durability in hard-use applications.

Are these barrels made in the USA? ▾

Yes. Faxon barrels are manufactured in-house in Greater Cincinnati, Ohio using vertically integrated machining and inspection processes.

Do Faxon Duty Series barrels include a warranty? ▾

All Faxon Firearms products are backed by our Limited Lifetime Warranty. For full warranty terms, service instructions, and exclusions, please visit: https://faxonfirearms.com/warranty-privacy-terms/