Green Mountain 300 BLK AR-15 Barrel 16" M4 Fluted Phosphate - GM-M27
$194.95
Only 1 left in stock
Upgrade your AR-15 build with the precision-engineered Green Mountain 300 BLK AR-15 Barrel. This 16-inch M4 fluted phosphate barrel delivers exceptional performance for .300 AAC Blackout enthusiasts seeking a reliable, versatile option for both suppressed and unsuppressed configurations.
Key Features and Benefits
- Optimized 1:7 Twist Rate – Stabilizes a wide range of 300 BLK projectiles, from lightweight supersonic loads to heavy subsonic rounds, ensuring tight groupings and consistent accuracy downrange.
- M4 Fluted Profile – Reduces overall weight while maintaining structural integrity, allowing for faster handling and reduced fatigue during extended shooting sessions without sacrificing rigidity.
- Mag Phosphate Finish – Provides durable corrosion resistance and a non-reflective matte appearance, ideal for tactical applications and harsh environments.
- Carbine-Length Gas System – Delivers reliable cycling with standard AR-15 components, promoting smooth operation and minimal recoil for improved follow-up shots.
- 5/8×24 Muzzle Threading – Compatible with a broad selection of muzzle devices, brakes, and suppressors for customized setups.
Technical Specifications
- Barrel Length: 16 inches
- Barrel Profile: M4
- Gas Block Journal: 0.750 inches
- Gas System: Carbine length
- Platform: AR-15
- Cartridge: 300 BLK / .300 AAC Blackout
- Twist Rate: 1:7
- Muzzle Thread: 5/8×24
- Finish: Mag Phosphate
- Weight: 30 oz
Why Choose This Green Mountain Barrel?
Built from premium 4150 chrome-moly vanadium steel with a chrome-lined bore and chamber, this barrel offers superior durability and easy cleaning. The fluted design enhances heat dissipation during rapid fire, while the M4 contour provides a balanced feel familiar to military-style platforms. Whether you’re building a home defense rifle, a plinker, or a suppressed hunting setup, this barrel addresses common pain points like excessive weight, poor subsonic performance, and finish degradation over time.
Engineered for precision and longevity, it integrates seamlessly into standard AR-15 uppers, giving builders confidence in every shot.
| Weight | 30 oz |
|---|---|
| Dimensions | 16 in |
| Finish | Mag Phosphate |
| Barrel Profile | M4 |
| Cartridge Compatibility | 300 BLK |
| Gas Block Journal | 0.75 |
| Barrel Length | 16" |
| Gas System Length | Carbine |
| Platform | AR-15 |
| Twist Rate | 1:7 |
| Muzzle Thread Pattern | 5/8×24 |
| MPN | GM-M27 |
| UPC | 33782 |
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.
