Green Mountain 5.56 AR-15 Barrel 20" M4 A2 Phosphate - GM-M17
$194.95
Out of stock
Upgrade your AR-15 build with the precision-engineered Green Mountain 5.56 AR-15 Barrel 20″ M4 A2 Phosphate. Designed for reliable performance in tactical and sporting applications, this barrel delivers the accuracy and durability serious shooters demand.
Key Features
- Chrome-lined bore and chamber for extended service life and easy maintenance, resisting wear from high-volume shooting.
- Phosphate finish provides corrosion resistance and a low-profile, non-reflective exterior suited for field use.
- Government/SOCOM profile balances strength and weight for enhanced handling without sacrificing rigidity.
- Rifle-length gas system ensures smooth cycling and reduced recoil impulse for consistent follow-up shots.
Technical Specifications
- Caliber: 5.56 NATO
- Length: 20 inches
- Twist Rate: 1:9
- Muzzle Thread: 1/2×28
- Gas Block Journal: 0.75 inches
- Platform: AR-15
- Weight: 37.2 ounces
Why Choose This Barrel
This M4 A2-style barrel addresses common pain points like barrel erosion and inconsistent accuracy by combining mil-spec construction with proven Green Mountain quality. The 1:9 twist stabilizes a wide range of bullet weights, making it versatile for both plinking and precision work. Built from high-quality steel with a chrome-lined interior, it withstands demanding conditions while maintaining tight tolerances for reliable feeding and extraction.
Whether you’re assembling a classic M4-style rifle or replacing an existing barrel, this component offers the features needed for dependable operation in any environment.
Benefits for Shooters
- Improved longevity reduces the need for frequent replacements.
- Optimized gas system promotes reliable function across ammunition types.
- Threaded muzzle allows easy suppressor or muzzle device installation for customization.
FAQs
What type of steel is used in this barrel?
Green Mountain barrels are manufactured from 41V50 chrome moly vanadium steel for superior strength and heat resistance.
Is this barrel compatible with standard AR-15 upper receivers?
Yes, it features an M4-style extension and fits standard AR-15 platforms with rifle-length gas systems.
How does the 1:9 twist rate perform?
The 1:9 twist effectively stabilizes common 5.56 NATO bullet weights from 55 to 77 grains, providing good accuracy for general-purpose and match loads.
| Weight | 37.2 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 | 1:9 |
| Muzzle Thread Pattern | 1/2×28 |
| MPN | GM-M17 |
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.
