Faxon Duty Series 13.9″ Big Gunner .308 WIN 4150 QPQ Nitride Mid-Length Barrel
The Faxon Firearms 13.9″ Big Gunner .308 WIN Mid-Length Barrel is purpose-built for AR-10 and LR-308 platforms, offering a superior balance of strength, reduced weight, and exceptional accuracy. This barrel features Faxon’s Big Gunner profile, which is designed with a medium taper behind the gas block for improved rigidity and a thinner taper forward to reduce unnecessary weight. The result is a high-performance option for shooters who need precision, reliability, and easier handling in one package.
Machined from 4150 CMV steel and treated with a QPQ salt bath nitride finish inside and out, this barrel is built for long-term durability and corrosion resistance. Its mid-length gas system contributes to smoother recoil impulse and reliable cycling, especially during sustained fire or when running suppressed. At 13.9 inches, it’s ideal for those planning to pin and weld a muzzle device to achieve an overall legal rifle length of 16 inches, offering flexibility without sacrificing performance.
With a 1:10 twist rate, the barrel is capable of stabilizing a wide range of .308 WIN projectiles, including match-grade and heavier grain options. The gas block journal measures .750″, and the muzzle is threaded 5/8×24 to support a wide variety of muzzle devices. The barrel also features a DPMS-compatible LR-308 barrel extension and an 11-degree target crown, both of which help deliver repeatable accuracy and proper fitment with most large-frame AR platforms. Magnetic particle inspection ensures each barrel meets Faxon’s strict quality standards before it ships.
Whether you’re building a precision rifle, compact field gun, or duty-grade AR-10, the 13.9″ Big Gunner delivers top-tier performance with a balanced feel that reduces front-end fatigue and improves control.
Product Information
| Length | 13.9" |
|---|---|
| Weight | 28.8oz |
| Finish | QPQ Nitride |
| Platform | AR10 |
| Series | Duty |
| Material | 4150 Chrome Moly Vanadium |
| Caliber | 308 Win |
| Twist Rate | 1:10 |
| Manufacturer | Faxon |
| Made in USA | Yes |
| Gas System | Mid-Length |
| Compatibility | Standard DPMS AR10 Components |
| Muzzle Thread | 5/8×24 |
| Gas Block Diameter | .750 |
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