Elevate Your AR-15 Performance: The Knights Armament SR-15 Mod 2 16.10" Upper Receiver Kit (Part No. 31962)

For serious firearms enthusiasts, competitive shooters, and professionals who demand uncompromising reliability and peak performance from their AR-15 platform, the Knights Armament (KAC) SR-15 Mod 2 Upper Receiver Kit stands as a benchmark of engineering excellence. This comprehensive kit transforms your AR-15 lower into a formidable, duty-ready rifle, leveraging KAC's decades of experience supplying the most elite military and law enforcement units worldwide. If you're searching for the best complete upper receiver for an AR-15, or how to significantly upgrade your existing build, this detailed overview will provide insights into why the KAC 31962 upper is a top-tier choice.

Who Is This Upper Receiver Kit For?

This Knights Armament upper is ideally suited for:

• AR-15 owners seeking a significant, immediate upgrade to their rifle's accuracy, durability, and operational reliability.
• Competitive shooters who require a rifle that can consistently perform under pressure, with excellent recoil management and rapid follow-up shot capability.
• Defense-minded individuals prioritizing a robust, military-grade firearm system for personal or home defense.
• Law enforcement and military personnel looking for a field-proven, dependable upper receiver that meets stringent operational demands.
• Discerning collectors who appreciate the craftsmanship, innovation, and historical significance of Knights Armament products.

This kit solves the problem of unreliable, inaccurate, or underperforming AR-15 uppers by providing a complete, meticulously engineered solution that integrates KAC's most advanced technologies. It's for those who aren't willing to compromise on quality or performance.

Unpacking the Engineering Brilliance: Key Features & Benefits

The KAC SR-15 Mod 2 16.10" Upper Receiver Kit (MPN: 31962) is not just an assembly of parts; it's a meticulously integrated system designed for superior function. Let's delve into the core components that make this upper receiver truly exceptional:

The SR-15 E3 Mod 2 5.56x45mm NATO Barrel: Precision and Longevity

At the heart of this upper is the 16.10-inch 5.56x45mm NATO barrel. Manufactured with military-grade durability in mind, this barrel is more than just a tube; it's a precisely crafted component built for sustained performance.

• Material and Construction: Crafted from high-quality chrome moly steel, known for its strength and resistance to wear. The barrel’s chambering in 5.56x45mm NATO means it can safely and effectively fire both 5.56mm NATO and .223 Remington ammunition, offering versatility to the shooter.
• Chrome Lining: While not explicitly stated in the initial content, KAC barrels often feature a chrome-lined bore and chamber. This process significantly increases the barrel's lifespan, enhances corrosion resistance, and simplifies cleaning, making it ideal for high-volume shooting and adverse conditions.
• Optimal Length: The 16.10-inch length strikes an excellent balance between maneuverability and ballistic performance. It provides sufficient velocity for the 5.56mm cartridge to perform effectively at typical engagement distances while keeping the overall rifle length manageable for close-quarters environments or vehicle operations.
• Twist Rate: With a 1:7" twist rate, this barrel is specifically optimized for stabilizing a wide range of projectile weights, particularly the heavier 62-grain (M855), 77-grain, and 75-grain projectiles commonly used for improved accuracy and terminal ballistics. This ensures excellent accuracy regardless of your preferred ammunition type.

The Revolutionary E3 Round-Lug Bolt Design

One of the most significant innovations in the SR-15 E3 Mod 2 system is its improved E3 round-lug bolt design. This patented design addresses common failure points found in standard AR-15 bolts, offering unparalleled durability and reliability.

• Enhanced Functionality: The E3 bolt features enlarged, radiused bolt lugs, which distribute locking forces more evenly across the bolt face and into the barrel extension. This reduces stress concentrations, significantly mitigating the risk of lug shearing, a common failure mode in standard AR-15 bolts.
• Increased Bolt Life: By reducing stress on the bolt lugs, the E3 design extends the bolt's service life far beyond the industry standard. This translates to fewer parts breakages, less downtime for maintenance, and a rifle that consistently runs when you need it most. For professionals, this enhanced durability is not just a convenience; it's a critical safety and operational advantage.
• Reliability in Adverse Conditions: The robust design of the E3 bolt, coupled with its enhanced extractor and ejector, contributes to exceptionally reliable cycling, even in harsh environments or with varying ammunition types. This is crucial for a firearm intended for serious use.

The 5.56mm 3-Prong Flash Eliminator

The muzzle device on the SR-15 Mod 2 upper is the KAC 5.56mm 3-Prong Flash Eliminator, a key component for reducing the rifle's visual signature.

• Superior Flash Suppression: This flash eliminator is designed to interfere with propellant gas combustion forward of the muzzle, significantly reducing the visible flash signature, especially in low-light conditions. This is critical for maintaining the shooter's night vision, concealing their position, and preventing temporary blindness from muzzle flash.
• No "Ringing" Signature: Unlike some other pronged flash hiders, the KAC 3-Prong Flash Eliminator is specifically engineered to eliminate the audible "ringing" sound that can occur upon firing or when the muzzle device is struck. This contributes to a more pleasant shooting experience and helps maintain stealth during tactical operations.
• QDC Signature Reduction Device Compatibility: A significant advantage of this flash eliminator is its compatibility with the Knight's line of 5.56mm Quick Detach Coupling (QDC) Signature Reduction Devices (suppressors). This allows for rapid and secure attachment and detachment of KAC suppressors, providing an integrated solution for reducing both flash and sound signature without the need for additional muzzle device changes. This seamless integration is a major draw for users planning to run suppressed.

The URX4 M-LOK Handguard: Modularity and Ergonomics

The barrel of the SR-15 Mod 2 is free-floated inside a URX4 M-LOK handguard, a design choice that enhances both accuracy and user customization.

• Free-Floated Design: A free-floated handguard means it does not make contact with the barrel beyond the barrel nut. This prevents any external pressure or tension from affecting barrel harmonics during firing, leading to improved accuracy and consistent point of impact.
• URX4 System: The URX4 is a monolithic rail system, meaning the upper receiver and handguard form a continuous top rail. This design enhances structural rigidity, ensuring that optics and aiming devices mounted across the receiver and handguard maintain their zero more consistently, even under heavy use.
• M-LOK Modularity: The M-LOK (Modular Lock) system is a popular and versatile attachment interface for accessories. It allows users to directly mount a wide range of accessories such as vertical grips, bipods, lights, lasers, and sling mounts directly to the handguard without the need for bulky Picatinny rail sections. This results in a lighter, sleeker, and more ergonomic handguard profile.
• Ergonomics and Heat Dissipation: The slim profile and strategic cutouts of the URX4 M-LOK handguard contribute to comfortable handling and efficient heat dissipation during sustained firing. This means your hands stay cooler, and your grip remains secure, even during extended shooting sessions.

Robust Aluminum Receiver with Flip-Up Sights

The upper receiver itself is constructed from durable aluminum, finished in a non-reflective black, matching the barrel and handguard for a cohesive look.

• Receiver Material: High-grade aluminum ensures a lightweight yet incredibly robust foundation for the entire upper assembly.
• Integrated Sights: This complete upper comes equipped with flip-up front and rear sights. These provide a reliable backup aiming solution, or can serve as the primary aiming system for users who prefer iron sights or are waiting to mount an optic. Their low-profile, foldable design ensures they don't interfere with mounted optics when not in use.

Why Choose a Knights Armament Upper Receiver Kit?

Investing in a Knights Armament upper receiver is a decision rooted in a desire for unparalleled quality and performance. Here's why KAC stands out:

• Proven Military Heritage: KAC products are not just "mil-spec"; they are often the military standard. Their equipment has been extensively tested and proven in the harshest combat environments by elite forces worldwide. When you purchase KAC, you're getting technology directly descended from battlefield-validated designs.
• Innovation and Proprietary Technology: KAC is renowned for its commitment to innovation. Features like the E3 bolt, the URX rail system, and their QDC suppressors are proprietary designs that offer tangible performance advantages over standard components.
• Uncompromising Quality Control: Every KAC product undergoes rigorous quality control and testing. This meticulous attention to detail ensures that each component meets the highest standards for fit, finish, and function.
• Long-Term Value: While the initial investment in a KAC upper may be higher than other options, their legendary durability, extended component life, and sustained performance often result in lower long-term costs of ownership and a higher resale value.
• Optimized System Integration: KAC designs their components to work together seamlessly as an integrated system. This holistic approach ensures maximum reliability, consistent performance, and ease of maintenance.

Real-World Applications and Use Cases

How does the Knights Armament SR-15 Mod 2 upper perform in various scenarios?

• Precision Shooting: The free-floated barrel, combined with the ideal 1:7" twist rate and rigid URX4 handguard, allows for exceptional accuracy, making it suitable for target shooting and even some competitive precision events.
• Tactical and Defensive Use: The robust E3 bolt, effective flash suppression, and durable construction make this upper an ideal choice for personal defense, home defense, and professional tactical applications where reliability is paramount. The M-LOK system allows for quick attachment of lights and lasers essential for these roles.
• Patrol and Duty Ready: For law enforcement officers, the SR-15 Mod 2 upper provides a duty-ready solution that can withstand the rigors of daily use and critical incidents, offering consistent performance when it matters most.
• Training and High-Volume Shooting: The extended life of the E3 bolt and the chrome-lined barrel (if applicable) makes this upper highly durable for extensive training courses and high-volume shooting, minimizing downtime and maintenance.

Enhancing Your AR-15: Installation and Compatibility

The Knights Armament SR-15 Mod 2 Upper Receiver Kit (UPC: 819064016069) is designed as a complete, drop-in solution for most mil-spec AR-15 lower receivers.

• Simple Installation: As a complete upper, installation is straightforward. Simply pin the upper receiver to your existing AR-15 lower receiver using the appropriate take-down pins. No specialized gunsmithing is typically required to get started.
• Compatibility: This upper is specifically designed for the SR-15 MOD 2 platform, but it will generally be compatible with any standard AR-15 lower receiver that adheres to mil-spec dimensions. Users should always verify compatibility with their specific lower.
• Accessories: The URX4 M-LOK handguard provides ample real estate for mounting a vast array of M-LOK compatible accessories. This includes foregrips, bipods, rail covers, weapon lights (e.g., SureFire, Streamlight), laser aiming modules, and sling attachment points. The continuous top Picatinny rail allows for seamless integration of optics, from red dot sights (e.g., Aimpoint, EOTech) to low-power variable optics (LPVOs) and magnified scopes.

Maintaining Your Investment

Proper care and maintenance will ensure the longevity and continued performance of your Knights Armament SR-15 Mod 2 upper.

• Cleaning: Regular cleaning of the barrel, bolt carrier group, and receiver internals is essential. The chrome-lined bore (if present) simplifies this process. Pay particular attention to the bolt's locking lugs and the chamber area.
• Lubrication: Adequate lubrication of all moving parts, especially the bolt carrier group and charging handle, is crucial for smooth operation and reliability. Use a quality firearm lubricant.
• Inspection: Periodically inspect the components for any signs of wear, damage, or loose parts. While the E3 bolt is designed for extreme durability, routine checks are always recommended.
• Storage: Store the upper in a clean, dry environment, preferably in a padded case or safe, to protect it from dust, moisture, and accidental damage.

The Value Proposition of Knight's Armament

When considering an upper receiver upgrade, many ask, "Is Knights Armament worth the investment?" The answer, for those who prioritize performance, reliability, and cutting-edge design, is a resounding yes. The KAC SR-15 Mod 2 upper is not merely a collection of parts; it's a meticulously engineered system that delivers a tangible advantage in reliability, accuracy, and shooter experience. It's built to run hard, last long, and perform flawlessly when stakes are highest.

This exceptional kit, like other premium Knight's Armament products, is available from reputable firearms retailers such as DEGuns, where you can find the expertise and inventory to complete your ultimate AR-15 build. When you choose a KAC upper, you're not just buying a product; you're investing in a legacy of innovation and a commitment to excellence that has been proven on battlefields and firing ranges around the globe.

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Product Specifications: Knights Armament 31962 Upper Receiver Kit

Feature	Detail
Brand	Knights Armament
Model	Upper Receiver Kit
MPN	31962
UPC	819064016069
Caliber	5.56x45mm NATO
Barrel Length	16.10"
Barrel Finish	Black
Barrel Material	Chrome Moly Steel
Twist Rate	1:7"
Muzzle Device	3-Prong Flash Eliminator
Handguard	URX4 M-LOK
Receiver Material	Aluminum
Receiver Finish	Black
Type	Complete
Sights	Flip Up Front & Rear
Firearm Fit	SR-15 MOD 2 (AR-Style Platform)
Weight	4.30 lbs
SKU	127171