Elevate Your AR-15 Build: Discover the CMMG 5.56 NATO 16.1" Midlength Barrel Sub-Assembly

Are you looking to build a custom AR-15 or upgrade your existing rifle with a component that promises superior performance and unwavering reliability? For discerning firearms enthusiasts, competitive shooters, and dedicated builders, the core of any accurate and dependable AR-15 lies in its barrel. The CMMG 55D590A Barrel Sub-Assembly in 5.56 NATO with a 16.1-inch length is an exceptional choice, engineered from premium 416R Stainless Steel to deliver the precision and durability that serious shooters demand. This component is not just a part; it's the heart of your next high-performance AR-15 project.

Why the Right AR-15 Barrel is Crucial for Performance

When embarking on an AR-15 build, or considering an upgrade, the barrel is often the most critical decision. It directly impacts accuracy, velocity, gas system function, and the overall longevity of your rifle. A high-quality barrel ensures consistent bullet flight, proper cycling, and the ability to withstand thousands of rounds fired. Poor barrel choice can lead to inconsistent groups, malfunctions, and premature wear. This is precisely why investing in a reputable component like the CMMG barrel sub-assembly is paramount for achieving your desired shooting experience.

Unpacking the CMMG 55D590A Barrel Sub-Assembly: Key Features and Their Benefits

The CMMG 5.56 NATO 16.1" Barrel Sub-Assembly is meticulously crafted with features designed to optimize your AR-15's capabilities. Let's delve into what makes this barrel a standout choice:

Premium 416R Stainless Steel Construction

• Material Excellence: This barrel is precisely machined from 416R Stainless Steel. What makes 416R a preferred material for rifle barrels? It's a specialized grade of stainless steel known for its exceptional corrosion resistance, superior machinability, and, most importantly, its ability to hold very precise rifling and maintain accuracy even after extensive use. Unlike other steel alloys, 416R is designed to withstand the heat and pressure of repeated firing cycles without degrading its structural integrity or accuracy potential.
• Durability and Longevity: The inherent properties of 416R steel contribute significantly to the barrel's lifespan, making it a reliable component for years of service. It resists pitting and erosion common in high-volume shooting, ensuring your rifle maintains its accuracy over a prolonged period.
• Consistent Accuracy: The metallurgical composition of 416R allows for extremely tight tolerances during manufacturing, resulting in a bore and rifling that are highly consistent, which translates directly into tighter shot groups downrange.

Optimal 16.1-inch Length and Midlength Gas System

• Versatile Length: At 16.1 inches, this barrel offers an excellent balance of maneuverability and ballistic performance. It's the shortest legal barrel length for a rifle without requiring an NFA (National Firearms Act) tax stamp, making it ideal for a wide range of applications from close-quarters training to general range use. This length also ensures efficient burning of propellants for common 5.56 NATO and .223 Remington ammunition.
• Midlength Gas System Advantage: The "Midlength" designation refers to the length of the gas tube and port placement. A midlength gas system on a 16-inch barrel provides several key benefits:
  • Smoother Recoil Impulse: The gas port is further down the barrel, allowing for a longer dwell time (the time gas pressure acts on the bolt carrier group). This results in a softer, more gradual recoil impulse compared to carbine-length systems, improving shooter comfort and enabling faster follow-up shots.
  • Reduced Wear and Tear: The less abrupt gas impulse puts less stress on internal components like the bolt carrier group, buffer, and recoil spring, contributing to increased parts longevity and overall rifle reliability.
  • Enhanced Reliability: The optimized gas flow ensures more consistent cycling across a wider range of ammunition types and environmental conditions.

Precision 1:7" Twist Rate

• Bullet Stabilization: The 1:7" twist rate means the bullet completes one full rotation for every 7 inches it travels down the barrel. This faster twist rate is highly effective at stabilizing a wide variety of 5.56x45mm NATO and .223 Remington bullet weights, particularly heavier, longer projectiles (62 grain, 77 grain, etc.).
• Versatility for Ammunition Types: If you plan to shoot a diverse range of ammunition, especially heavier "match" or duty rounds, a 1:7" twist is often recommended for maximizing accuracy. While it can also stabilize lighter bullets, its primary benefit shines with projectiles designed for longer ranges or enhanced ballistic performance.

Crucial M4 Barrel Extension with Feed Ramps

• Pre-Installed for Easy Assembly: The CMMG barrel comes with the M4 barrel extension properly installed. This is a critical feature, as the extension houses the locking lugs that mate with the bolt and provides the feed ramps.
• Reliable Feeding: M4 feed ramps are extended cuts that seamlessly integrate with the feed ramps in an M4-style upper receiver. This creates a larger, smoother path for rounds to feed from the magazine into the chamber, significantly reducing the chance of feeding malfunctions, especially during rapid fire or in adverse conditions. This pre-installed, precisely aligned component simplifies your build process and ensures optimal function.

Threaded Muzzle (1/2"-28) and Bead Blasted Finish

• Muzzle Device Compatibility: The 1/2"-28 thread pattern is the standard for 5.56 NATO/.223 Remington barrels, allowing for the easy attachment of a wide array of muzzle devices, including flash hiders, compensators, muzzle brakes, and sound suppressors. This versatility is essential for customizing your rifle's recoil mitigation, muzzle flash signature, or sound suppression needs.
• Aesthetic and Protective Finish: The "Bead Blasted" finish gives the stainless steel a uniform, matte, non-reflective appearance. Beyond aesthetics, this finish can also offer a degree of surface protection and reduce glare, which can be advantageous in various shooting environments.

Who Benefits Most from the CMMG 55D590A Barrel Sub-Assembly?

This barrel is an ideal choice for a specific group of users and builders:

• DIY AR-15 Builders: If you're undertaking a new AR-15 build from scratch, this CMMG barrel provides a high-quality, pre-assembled foundation for your upper receiver group, saving you time and ensuring critical components are correctly installed.
• AR-15 Upgraders: For owners looking to replace a worn-out barrel or enhance the accuracy and performance of an existing AR-15, this CMMG sub-assembly offers a significant upgrade path.
• Precision Shooters: The 416R stainless steel and 1:7" twist rate make this barrel excellent for shooters who prioritize consistent accuracy, especially with heavier projectiles.
• Competitive Shooters: The midlength gas system's smoother recoil impulse can be a considerable advantage in timed shooting drills, allowing for faster target acquisition and follow-up shots.
• Reliability Seekers: Anyone who values a rifle that performs consistently under various conditions will appreciate the engineering and material quality of this CMMG component.

Common Questions This CMMG Barrel Answers

As you plan your AR-15 project, you might be asking:

• "What's the best barrel material for AR-15 accuracy?" The 416R Stainless Steel used in this CMMG barrel is highly regarded for its precision potential and corrosion resistance, making it an excellent choice for accuracy-focused builds.
• "How does barrel length affect my AR-15?" The 16.1-inch length offers a versatile balance, providing good velocity for the 5.56 NATO cartridge while remaining maneuverable and legally compliant as a rifle.
• "Which twist rate do I need for 5.56 NATO?" The 1:7" twist rate of this CMMG barrel is optimized for stabilizing a broad range of 5.56/.223 ammunition, particularly heavier grain bullets, which are popular for their ballistic performance.
• "What are the benefits of a midlength gas system?" A midlength system, as featured on this CMMG barrel, provides a softer recoil impulse and reduces wear on your rifle's internal components, contributing to a more pleasant shooting experience and extended rifle lifespan.
• "Is building an AR-15 upper difficult?" While it requires some tools and knowledge, components like this CMMG barrel sub-assembly, with its pre-installed M4 barrel extension, simplify the process, ensuring critical interfaces are correctly aligned from the start.

The CMMG Advantage: A Legacy of Quality and Innovation

CMMG has established itself as a reputable name in the firearms industry, known for its commitment to quality, innovation, and producing reliable components and complete firearms. When you choose a CMMG barrel, you're investing in a product backed by years of manufacturing expertise and a dedication to meeting the rigorous demands of shooters and builders alike. Their components are designed with precision and attention to detail, ensuring compatibility and peak performance within the AR-15 platform. This trust in the CMMG brand is a significant factor for many who seek to build or upgrade their rifles with confidence, knowing they are selecting a proven and respected component.

Building Your Upper Receiver Group with the CMMG Barrel

The CMMG 55D590A Barrel Sub-Assembly serves as the core for your AR-15 upper. To complete your upper receiver group, you will typically need to pair it with:

1. An AR-15 upper receiver (preferably one with M4 feed ramp cuts to match the barrel extension).
2. A gas block (compatible with .750" gas block journals, which is standard for many AR-15 barrels).
3. A midlength gas tube.
4. A compatible handguard/rail system.
5. A muzzle device (flash hider, brake, suppressor, etc.).

The pre-installed M4 barrel extension on the CMMG sub-assembly simplifies the barrel installation process into your upper receiver, making it more straightforward for both novice and experienced builders.

Where to Acquire Your CMMG Barrel Sub-Assembly

For those ready to experience the difference a high-quality CMMG barrel makes, the CMMG 55D590A Barrel Sub-Assembly is available from trusted retailers like DEGuns.com. DEGuns offers a wide selection of firearm components, ensuring you can find everything you need to complete your build or upgrade project with confidence. Their commitment to customer satisfaction and access to top-tier brands like CMMG makes them a reliable source for your firearms needs.

Final Thoughts: A Foundation for Precision and Reliability

In summary, the CMMG 55D590A Barrel Sub-Assembly is an exceptional component for anyone serious about the performance of their AR-15. Its 416R Stainless Steel construction, precise 1:7" twist rate, 16.1-inch midlength configuration, and pre-installed M4 barrel extension all converge to deliver accuracy, durability, and a smooth shooting experience. Whether you are assembling a new custom AR-15 or breathing new life into an existing rifle, this CMMG barrel provides the robust and reliable foundation necessary for peak performance. Invest in quality; invest in CMMG at DEGuns.com, and build an AR-15 that truly stands out.

CMMG Barrel Sub-Assembly Specifications

Feature	Detail	Notes
Brand	CMMG	Leading AR-15 component manufacturer
Model	Barrel Sub-Assembly	Ready for custom builds
Caliber	5.56x45mm NATO	Also compatible with .223 Remington
Firearm Fit	AR-15	Standard platform compatibility
Length	16.10 inches	Optimal legal rifle length
Material	416R Stainless Steel	For accuracy and corrosion resistance
Finish	Bead Blasted	Non-reflective, durable surface
Barrel Type	Midlength	Smoother recoil, reduced wear
Twist Rate	1:7"	Stabilizes wide range of bullet weights
Thread Pattern	1/2"-28	Standard for muzzle devices
Included Features	M4 Barrel Extension	Pre-installed for reliable feeding
Manufacturer Part #	55D590A	Unique product identifier
UPC	815835016160	Universal Product Code