Dirty Bird Bakersfield
Out of stock
Description
Discover the precision and reliability of the Green Mountain 5.56 AR-15 Barrel 20″ M4 A2 Phosphate. Designed for serious shooters and custom AR-15 builders, this barrel delivers consistent accuracy and long-term durability in a classic government-profile configuration.
Key Features and Benefits
- Chrome-lined bore and phosphate finish – The chrome lining protects against corrosion and wear, extending barrel life while the durable phosphate coating resists harsh conditions, ensuring reliable function during extended range sessions or tactical use.
- M4 A2 government profile with 0.75″ gas block journal – This balanced profile reduces weight without sacrificing strength, providing excellent handling and heat dissipation for sustained fire.
- 1:7 twist rate – Optimized for stabilizing a wide range of 5.56 NATO and .223 Remington projectiles, including heavier match-grade bullets for enhanced accuracy at distance.
- Rifle-length gas system – Delivers smooth, reliable cycling with reduced recoil impulse compared to shorter systems, ideal for precision builds and suppressed configurations.
- 1/2×28 muzzle threading – Ready for a variety of muzzle devices, flash hiders, or suppressors to customize your setup.
Technical Specifications
- Barrel Length: 20 inches
- Cartridge Compatibility: 5.56 NATO / .223 Remington
- Platform: AR-15
- Twist Rate: 1:7
- Gas System: Rifle length
- Gas Block Journal: 0.75 inches
- Finish: Phosphate with chrome-lined bore
- Muzzle Thread: 1/2×28
- Weight: 37.6 oz
Why Choose This Green Mountain Barrel?
Green Mountain barrels are manufactured to tight tolerances for consistent performance. The combination of a chrome-lined interior and robust phosphate exterior makes this 20″ M4 A2 barrel an excellent choice for those seeking a proven, no-nonsense component that withstands rigorous use while maintaining sub-MOA potential in a properly assembled rifle.
Whether you are building a classic M4-style carbine or upgrading an existing AR-15, this barrel provides the foundation for reliable feeding, extraction, and accuracy. Its rifle gas system pairs well with standard buffers and springs, minimizing the need for extensive tuning.
Installation and Compatibility Notes
This barrel is compatible with standard AR-15 upper receivers and requires a low-profile or standard gas block sized for the 0.75″ journal. Professional installation is recommended to ensure proper headspace and alignment.
Additional information
| Weight | 37.6 oz |
|---|---|
| Dimensions | 20 in |
| Finish | Phosphate + Chrome Lined |
| Barrel Profile | Government / SOCOM |
| Cartridge Compatibility | 5.56 NATO |
| Gas Block Journal | 0.75 |
| Barrel Length | 20 |
| Gas System Length | Rifle |
| Platform | AR-15 |
| Twist Rate | 1:7 |
| Muzzle Thread Pattern | 1/2×28 |
| MPN | GM-M16 |
Compliance
NFA (National Firearms Act) compliance is crucial for legal ownership and transfer of regulated firearms and accessories like short-barreled rifles, suppressors, and certain types of ammunition, ensuring adherence to federal regulations to avoid legal penalties and ensure responsible firearm ownership.
