Knights Armament SR-15 KS-3 5.56 NATO 11.5" Assembled Upper Receiver – Ultra-Compact Tactical Upper
The Knights Armament SR-15 KS-3 5.56 NATO 11.5" Assembled Upper Receiver (121437) is the most compact model in the KS-series, designed for operators and shooters who require maximum maneuverability in close-quarters environments. Featuring an 11.5-inch barrel and a modern M-LOK handguard, this factory-assembled upper delivers exceptional reliability and performance in the shortest possible package. Built to the same rigorous standards trusted by elite military and law enforcement units, the SR-15 KS-3 provides a premium, ready-to-install solution for building an ultra-compact short-barreled rifle or upgrading an existing SR-15 lower receiver.
Knights Armament continues to lead the industry with high-quality, purpose-built components. The KS-3 model represents the pinnacle of compactness in the SR-15 lineup while maintaining the brand’s renowned standards of accuracy and durability.
Key Features of the Knights Armament SR-15 KS-3 5.56 NATO Assembled Upper
11.5-Inch Barrel
The shortest barrel in the KS-series, offering maximum maneuverability and the most compact overall length for close-quarters battle and confined space operations.
Factory Assembled
Comes fully assembled with upper receiver, barrel, bolt carrier group, and handguard, ensuring proper headspacing and reliable function straight out of the box.
M-LOK Handguard
Modern M-LOK compatible handguard provides a lightweight and versatile mounting platform for accessories while maintaining a slim, comfortable profile.
Why Choose the Knights Armament SR-15 KS-3 5.56 NATO 11.5" Assembled Upper Receiver?
When searching for the most compact 5.56 NATO assembled upper receiver available, the Knights Armament SR-15 KS-3 5.56 NATO 11.5" Assembled Upper Receiver (121437) stands out as the ultimate choice for tactical professionals and serious builders. The SR-15 platform has earned a reputation for exceptional reliability, accuracy, and durability under the harshest conditions. This assembled upper allows users to quickly build an ultra-compact short-barreled rifle by pairing it with a compatible SR-15 lower receiver. The 11.5-inch barrel is the defining feature of the KS-3 model. This ultra-short barrel length provides the greatest level of maneuverability in the SR-15 KS series, making it ideal for close-quarters battle (CQB), vehicle operations, room clearing, and any scenario where a compact rifle is essential. While shorter barrels naturally produce lower muzzle velocity than longer barrels, the 11.5-inch length still delivers effective terminal performance at typical CQB and short-to-medium engagement distances when using quality 5.56 NATO ammunition. One of the biggest advantages of purchasing a factory-assembled upper from Knights Armament is the assurance of quality and proper assembly. Each upper is carefully built and inspected at the factory, ensuring correct headspacing, proper torque specifications, and reliable function. This saves builders significant time and eliminates the need for specialized tools or professional gunsmithing services. The M-LOK handguard offers a modern, lightweight mounting solution that allows shooters to customize their rifle with lights, lasers, grips, and other accessories without adding unnecessary weight. The slim profile improves handling comfort while providing ample real estate for attachments. Combined with Knights Armament’s precision-machined upper receiver and high-quality components, this assembled upper delivers the fit, finish, and performance the brand is famous for. The SR-15 KS-3 upper receiver is compatible with standard AR-15 lower receivers and magazines. Its black finish provides a professional, tactical appearance while offering good corrosion resistance. Whether you are building an ultra-compact short-barreled rifle, replacing an existing upper, or looking for a high-quality 5.56 NATO upper for a specialized project, the Knights Armament SR-15 KS-3 11.5" Assembled Upper Receiver offers exceptional value and performance. Investing in a Knights Armament upper receiver means owning a component built to the same standards as those used by elite military and law enforcement units. The SR-15 KS-3 delivers the reliability, accuracy, and quality that serious shooters expect from one of the most respected names in the firearms industry.
- Knights Armament SR-15 KS-3 Assembled Upper Receiver
- Chambered in 5.56 NATO
- 11.5-Inch Barrel
- M-LOK Compatible Handguard
- Factory Assembled and Inspected
- Black Finish
- Premium Fit and Finish
- Ready to Install on SR-15 Lower Receiver
- Maximum Maneuverability and Compactness
- Model: 121437
Technical Specifications – Knights Armament SR-15 KS-3 5.56 NATO Upper
| Specification | Details |
|---|
| Brand | Knights Armament |
| Model | SR-15 KS-3 |
| Part Number | 121437 |
| Caliber | 5.56 NATO |
| Barrel Length | 11.5 Inches |
| Handguard | M-LOK |
| Configuration | Assembled Upper Receiver |
| Finish | Black |
| Key Benefits | Ultra-Compact Size, Maximum Maneuverability, Premium Quality |
| Best For | Close-Quarters Battle, Vehicle Operations, Short-Barreled Rifle Builds |
Shop the Knights Armament SR-15 KS-3 5.56 NATO 11.5" Assembled Upper Receiver today.
The Knights Armament SR-15 KS-3 5.56 NATO 11.5" Assembled Upper Receiver (121437) is a premium, factory-assembled upper featuring an ultra-compact 11.5-inch barrel and M-LOK handguard. Chambered in 5.56 NATO, this complete upper offers exceptional reliability, accuracy, and maximum maneuverability. Ready to install on a compatible SR-15 lower receiver, it is finished in black and built to the highest standards by Knights Armament. Ideal for close-quarters battle, short-barreled rifle builds, and tactical professionals seeking the most compact 5.56 NATO upper receiver. Part Number: 121437.
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