.jpeg "11.5″ 5.56 NATO AR-15 Barrel — 4150 CMV, M4 Contour, 1:7 Twist, Carbine Gas, photo")
11.5″ AR-15 Barrel — 4150 CMV, M4 Contour, 1:7 Twist (5.56 NATO / .223)
Upgrade your AR-15 build with this premium 11.5″ barrel, crafted in the USA for performance and reliability. This barrel features rugged 4150 Chrome Moly Vanadium (CMV) steel, an M4 contour with M4 style feed ramps, optimized carbine-length gas system, and a fast 1:7 twist rate — designed for serious shooters who demand accuracy, durability and flexibility.
Key Features
- Chamber / Caliber: 5.56 NATO (also shoots .223 Remington)
- Length: 11.5″ — compact, maneuverable, ideal for short-barrel builds
- Material: 4150 Chrome Moly Vanadium (CMV) steel
- Profile: M4 contour with M4 feed ramps for optimal compatibility with Mil-Spec uppers
- Twist Rate: 1:7 — stabilizes heavier 5.56/.223 bullets (62 gr and up) for long-range potential
- Gas System: Carbine-length gas for reliable cycling in compact builds
- Gas Journal Diameter: .750″ — fits standard .750″ gas blocks
- Muzzle Threads: 1/2-28 — compatible with a wide range of muzzle devices
- Manufactured: Made in the USA, backed by Mid State Firearms quality assurance
Why Choose This Barrel from Mid State Firearms?
When you build with Mid State Firearms, you’re getting more than just parts — you’re getting experience and precision engineering. Our 11.5″ barrel offers the sweet spot between compact maneuverability and ballistic potential. With the 1:7 twist, you’re equipped to shoot heavier bullets, match loads or standard 5.56 ammunition with confidence. Well thought out builds using shorter barrels like the 11.5″ require careful gas system design and quality steel to perform reliably.
Whether you’re configuring a pistol-upper, a short carbine or a tactical build, this barrel offers outstanding value and performance. Choose Mid State Firearms and build a rifle you can trust.
Compatibility & Build Notes
- This barrel is designed for AR-15 pistol uppers or others where short length is required. Check local, state and federal laws (including NFA rules) if you are building an SBR or pistol configuration.
- Fits standard AR-15 barrel nuts, .750″ gas blocks and 1/2-28 muzzle devices.
- Proper installation, including torqueing of the barrel nut, alignment of the gas tube, and headspace verification, is strongly recommended. Consult a qualified gunsmith if needed.
Installation Tips & Accessories
For optimal performance, pair this barrel with a free-float handguard that suits the 11.5″ length, a quality .750″ gas block, proper gas tube length, and a compatible muzzle device. Browse our other AR-15 components at Mid State Firearms to complete your build:
- Other 5.56 NATO / .223 barrels
- Short-barrel AR-15 barrels (10.5″, 11.5″, 12.5″)
- How to choose an AR-15 barrel — build guide
- Ar15 Compatible Handguards
Quick Specs Table
| Caliber / Chamber | 5.56 NATO (.223 compatible) |
| Length | 11.5″ |
| Material | 4150 Chrome Moly Vanadium (CMV) |
| Profile | M4 contour with M4 feed ramps |
| Twist Rate | 1:7 |
| Gas System | Carbine length |
| Gas Journal Diameter | .750″ |
| Muzzle Threads | 1/2-28 |
| Made In | USA |
Note: Always verify your local and federal regulations when building short-barrel uppers or pistol configurations. Mid State Firearms is happy to assist with fitment or compatibility questions — contact us any time.
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sound of freedom – This was a great set up. I loved being able to customize the set up. Only issue I had was my own fault as a newb to building these. I used a heavy barrel in a slim hand guard. It makes adding attachments tough with clearances. Hoping someday to also get an AR10 from here.