Sons Of Liberty Gun Works M4-89 5.56x45 NATO 13.7'' Barrel Upper with 13'' M89 Rail & NOX Brake - M489UPPER-13.7-556-B
Experience unmatched reliability and precision with the Sons Of Liberty Gun Works (SOLGW) M4-89 Upper Receiver – model M489UPPER-13.7-556-B. Chambered in 5.56x45 NATO, this combat-ready 13.7-inch barrel AR-15 upper features a premium 13'' M89 Rail and NOX Muzzle Brake for superior control and modularity. Built for duty, range domination, or home defense, the SOLGW M4-89 is the ultimate upgrade for serious shooters seeking SOLGW uppers.
Premium Features of the SOLGW M4-89 Upper
- 13.7'' CMV 4150 Barrel: Government-profile, nitride-treated for extreme durability, accuracy, and heat resistance in 5.56 NATO.
- 13'' M89 Rail System: Free-float M-LOK handguard for endless accessory mounting – lights, grips, optics, and more.
- NOX Muzzle Brake: Advanced flash-hider and recoil reducer minimizes muzzle rise for faster follow-ups.
- Full-Auto Rated BCG: SOLGW proprietary bolt carrier group with enhanced extractor and ejector for flawless cycling.
- Mil-Spec Charging Handle: Ambidextrous compatibility for smooth operation under stress.
- Pinned & Welded Gas Block: Low-profile design ensures reliability without forward assist interference.
- 7075-T6 Forged Upper: Hardcoat anodized for corrosion resistance and lightweight strength.
Why the Sons Of Liberty M4-89 Upper Excels
Sons Of Liberty Gun Works sets the standard for AR-15 uppers with battle-tested designs inspired by military specs. The M4-89 13.7'' 5.56 upper delivers pinpoint accuracy out to 500+ yards, suppressed or unsuppressed. "This thing runs like a dream – zero malfunctions after 5,000 rounds!" raves a SOLGW user. Perfect for building custom AR-15 rifles, SBRs, or completing your lower, it's optimized for mid-length gas system efficiency.
Top search terms like SOLGW M4-89, 13.7 inch 5.56 upper, M89 rail upper, and NOX brake AR upper lead straight to this beast. Proudly made in the USA with a lifetime warranty – because SOLGW builds uppers that last.
Compatibility & Detailed Specifications
| Specification | Details |
|---|
| Model Number | M489UPPER-13.7-556-B |
| Caliber | 5.56x45 NATO / .223 Remington |
| Barrel Length | 13.7 inches |
| Rail Length | 13'' M89 M-LOK |
| Muzzle Device | NOX Brake |
| Gas System | Mid-Length |
| Barrel Material | 4150 CMV Nitride |
| Weight | Approx. 3.2 lbs (complete upper) |
| Compatibility | Mil-Spec AR-15 Lowers |
What Shooters Are Saying
"SOLGW M4-89 is the best 13.7 5.56 upper money can buy. Laser accurate and tough as nails." – Mike R., NC
"M89 rail is game-changing for my build. NOX brake tames the recoil perfectly!" – Tactical Tim, AZ
Build Your Dream AR-15 Today
Don't settle for lesser uppers – the Sons Of Liberty Gun Works M489UPPER-13.7-556-B is engineered for excellence. Ideal for AR builders, 3-gun competitors, or patriots defending freedom. Pair it with your favorite lower, optic, and suppressor for a setup that outperforms the competition.
Limited stock – secure your M4-89 upper now!
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