4.5" 1:10 Twist 9mm Barrel - Black Nitride

Build the ultimate ultra-compact AR-9 pistol or Pistol Caliber Carbine (PCC) with the Always Armed 4.5" 9mm Black Nitride Barrel. Tailor-made for backpack builds, home defense setups, and subcompact firearms, this short-profile barrel delivers maximum maneuverability without sacrificing accuracy or structural integrity.

Precision-machined from ultra-durable 4150 Chrome Moly Vanadium (CMV) steel, this barrel features an advanced QPQ Black Nitride finish. This surface treatment creates an exceptionally hard, corrosion-resistant barrier both inside the bore and on the exterior surface to withstand high-volume, rapid-fire sessions. An integrated 11-degree target crown protects the muzzle rifling and promotes clean gas dispersal for consistent accuracy at close-to-mid ranges.

The 1:10 right-hand twist rate provides ideal stabilization for popular 9mm bullet weights, including standard 115gr, 124gr, and heavy 147gr subsonic rounds. Threads are precision-cut to the classic 1/2x36 TPI pitch, preventing cross-threading with standard 5.56 muzzle devices and allowing direct fitment of standard 9mm flash hiders, compensators, or suppressors.

Technical Specifications

• Brand: Always Armed
• Caliber: 9mm (9x19mm Parabellum)
• Length: 4.5 Inches
• Material: 4150 Chrome Moly Vanadium (CMV) Steel
• Finish: QPQ Black Nitride
• Twist Rate: 1:10
• Crown: 11-Degree Target Crown
• Thread Pitch: 1/2x36 TPI
• Platform: AR-9 / AR-15 9mm Uppers