Green Mountain 5.56 AR-15 Barrel 20" M16 A1 Phosphate - GM-M15
$194.95
Only 3 left in stock
Upgrade your AR-15 build with the Green Mountain 5.56 AR-15 Barrel 20″ M16 A1 Phosphate, a precision-engineered component designed for shooters who demand accuracy, durability, and authentic M16-style performance. Crafted to exacting standards, this barrel delivers reliable function in both recreational and tactical applications while supporting modern 5.56 NATO ammunition.
Key Features and Benefits
- Chrome-lined bore and chamber with phosphate exterior finish – Provides exceptional corrosion resistance and extended service life, reducing maintenance needs and ensuring consistent performance in varied conditions.
- Government / SOCOM profile with rifle-length gas system – Offers a balanced weight distribution for improved handling and reduced recoil, ideal for precision shooting or duty use.
- 0.625″ gas block journal and 1/2×28 muzzle threads – Ensures compatibility with standard low-profile gas blocks and a variety of muzzle devices for custom configurations.
- M16-style extension and 20-inch length – Delivers classic ergonomics and velocity for effective terminal performance at longer ranges.
Technical Specifications
- Platform: AR-15
- Caliber: 5.56 NATO
- Barrel Length: 20 inches
- Twist Rate: 1:12
- Gas System: Rifle length
- Gas Block Journal: 0.625 inches
- Muzzle Thread: 1/2×28
- Finish: Phosphate with chrome-lined bore and chamber
- Barrel Profile: Government / SOCOM
- Weight: 35.4 ounces
Why Choose This Product
This barrel addresses common pain points for AR-15 builders, such as inconsistent accuracy with varying ammunition and premature wear in harsh environments. The robust construction from premium materials ensures tight tolerances for reliable feeding, extraction, and grouping. Whether restoring a classic M16A1 replica or building a modern tactical rifle, it provides the foundation for dependable operation without compromising on quality or compatibility.
Invest in a barrel that combines proven design with contemporary performance enhancements for years of trusted service.
| Weight | 35.4 oz |
|---|---|
| Dimensions | 20 in |
| Finish | Phosphate + Chrome Lined |
| Barrel Profile | Government / SOCOM |
| Cartridge Compatibility | 5.56 NATO |
| Gas Block Journal | 0.625 |
| Barrel Length | 20 |
| Gas System Length | Rifle |
| Platform | AR-15 |
| Twist Rate | 1:12 |
| Muzzle Thread Pattern | 1/2×28 |
| MPN | GM-M15 |
| UPC | 33771 |
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.
