Knight's Armament SR-15E3 IWS Mod 2 Keymod Upper Receiver Assembly, 16"

Knight's Armament
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Knight's Armament SR-15E3 IWS Mod2 Upper Receiver Assembly, 16" Barrel

The SR-15 Mod 2 Upper Receiver Assembly is crafted to outperform its competitors through a rugged, hard-use lifespan.

The Knight's Armament SR-15E3 IWS Mod2 Upper Receiver Assembly Includes:

  • 16 Inch Chrome Lined Barrel With New Mod 2 Gas Block

  • 200-600m Knight's Armament Micro Rear Sight

  • Knight's Armament Micro Front Sight

  • E3 Round Lug Enhanced Bolt, designed to outlast the barrel

  • M16 Full Auto Bolt Carrier, Chrome Lined

  • Knight's Armament URX 4 Keymod Handguard, 14"

  • Knight's Armament 3 Prong Flash Hider, Accepts Knight's QDC Suppressors

  • Knight's Armament Keymod Handguard Panels (7)

  • Knight's Armament Keymod Picatinny Rail, 5 Slot

Knight's Armament Company Background & History

More than 30 years ago, Knight’s Armament Company (KAC) was founded as a Research and Development facility. Today, Knight’s Armament is a premier weapons manufacturer which offers complete weapon systems, Knight Vision electro-optics and modular accessories. All research and development, manufacturing, assembly and testing is performed at their facility in Titusville, Florida. Knight’s Armament is widely recognized for their advanced developments in weapon designs and accessories. Knight’s Armament was originally founded by C. Reed Knight Jr, who strove to bring products to the table to meet the needs of U.S. Special Forces. KAC collaborated with Mr. Eugene Stoner who helped develop some of the most innovative modern weapon designs ever to exist. Knight and Stoner were the driving forces behind their renowned weapon systems, patented rail system and the Knight Vision electro-optics. Units from all branches of the United States military and numerous Law Enforcement entities depend on the enduring reliability of Knight’s Armament weapons and accessories. The mission of the development and manufacturing process for Knight’s Armament is to produce weapon systems that perform consistently and reliably for all, when it matters most.

Knight's Armament SR15 Complete Upper Description

The Knight's Armament Stoner Rifle 15 series (SR15) is a semi-automatic rifle featuring a 16 inch chrome lined barrel with a new mod 2 gas block. The SR15 also features a 200-600m Knights Armament Micro Rear Sight, Knight's Armament Micro Front Sight and a E3 Round Lug Enhanced Bolt, which is designed to outlast the barrel and a chrome lined M16 full auto bolt carrier. This enhanced complete package also includes a 14 inch Knight's Armament URX 4 Keymod Handguard, a Knight's Armament 3-prong flash hider that accepts Knight's Armament QDC suppressors, (7) Knight's Armament Keymod Handguard Panels, and a Knight's Armament 5-slot Keymod Picatinny rail. The Knight's Armament SR-15 is the first rifle model with an Integral Weapons System (IWS) that includes the best built-in and modular features that are built to persevere through heavy use.

SR-15E3 IWS Upper Receiver Assembly Mod 2

The SR-15 E3 IWS Upper Receiver Assembly Mod 2 now includes an upgraded URX 3.1 rail system with a longer overall length to help increase muzzle stabilization. This upgrade also reduces weight by taking away the frequently unused rail section of the system. This system also continues to provide a comfortable grip while allowing users who have a thinner rail diameter the ability to still mount their desired accessories on the front end of the firearm.

E3 Enhanced Bolt

The Knight's Armament E3 Enhanced Bolt is the most durable and reliable bolt available, featuring various components which are designed for maximum performance. This bolt is designed specifically for SR15 and 16 models. The E3 bolt includes features that contribute to top performance overall. These features include an enlarged bolt face, rounded lugs, proprietary extractor and firing pin designs and reduced cam pin. The enlarged bolt face incorporated into the E3 Bolt design provides more positive engagement in the chamber and rounded lugs which are designed to specifically reduce cracking, snapping and chipping. The life of the bolt becomes extended due to the strength of the design, and a proper seating is ensured each time the firearm cycles.

The design of the E3 Bolt extractor was developed to perform with the utmost reliability. The E3 bolt extractor has been referred to as a “butterfly” shape as it visually appears as a rounded “T” form. The extractor pivot point is shifted forward in order to balance out the extractor while applying constant pressure on the shell. This feature reduces the possibility of extraction failures immensely. In addition, this extractor uses two full-size extractor springs compared to just the standard micro-spring. While the extractor is in motion, a reduction of relative compression is allowed, which produces a failsafe in case one of the springs were to be pushed to failure. This innovative design allows the user the ability to continue with their mission or firing schedule because the bolt will still continue to function properly.

Knight's Armament reduced the overall size of the E3 Bolt by developing a thinner Cam Pin and Firing Pin. The thinner Cam Pin allows for a thicker bolt web which is a common failure point in normal bolts. The idea to decrease the size of the firing pin was designed around accommodating the thinner Cam Pin. The E3 Bolt outshines in performance when it is under the full auto firing configuration or extremely high cyclic rates. It was also created to perform effortlessly under casual firing conditions. The Knight's Armament E3 Bolt goes above and beyond expectations for durability and service life and was specifically created to put out high performance during ceaseless, stressful conditions.

Hammer Forging

The hammer-forging process employed in producing a number of Knight's Armament  barrels and chambers serves to increase the quality of their interior finish, as well as increasing the durability and life of the barrel. This process also enhances the quality of the interior finish. In addition, the barrels are chrome-lined to add to the lifespan of the barrel and deepen its resistance to corrosion and fouling.

When crafting these barrels Knight's Armament first takes a drilled barrel and hones the interior to a clean finish. Next, the barrel is fitted over a mandrel with the rifling pattern across it. The barrel is then centered between opposing power hammers which form the barrel precisely around the mandrel pattern. The barrel is simultaneously rotated and the hammers forge the barrel into its final shape. After this step, the barrels are heat treated in order to mitigate the innate stress created during the forging process. After the hammer forging, the barrel goes through the chroming process. The interior of the barrel gets lined with a layer of chrome which becomes affixed to the forged steel. One advantage of chroming consists of chrome being approximately twice as hard as standard 4150 steel. Chroming also protects a normally porous barrel from lead and powder. The end result of chroming allows the barrel to be exposed to higher pressures and temperatures from high firing schedules and simultaneously maintain accuracy, durability and reliability. The denser, strengthened barrel can withstand a higher round life compared to a standard stainless steel barrel or chrome moly barrel.

Universal Rail Extending (URX) 

The Knight's Armament Universal Rail Extending (URX) began 20+ years ago while Knight's began to originate the Modular Weapon System. The Knight's Armament URX is a free-floating, continuous top rail system that is lightweight and was designed to allow the user the greatest assortment of placement options for any of their desired mountable accessories.

The URX component was created to be free-floating which is an effort to mitigate all weight, contact and stress from the barrel. The barrel does not support the rail system which means the rail system only comes into contact with the receiver. When the firearm’s barrel is heating up and succumbs to greater stress under high firing schedules, this rail system ensures accuracy by allowing the mounted accessories to have no effect on its performance.

Knight's Armament produces many variations of the URX to meet your needs. The rail systems come in varying lengths ranging from the URX Carbine at 7” to the URX 3.1 7.62 at 14”.  The latest rail systems from Knight's Armament are the URX 3.1 systems which employ a flat, continuous top rail, a length of mounting rails at both ends of the sides and bottom, and slick sided portions in the middle section of the rail. The slick sided sections allow a slimmer diameter to help the user maintain a good grip while also contributing to an overall reduction in weight. The URX II models integrate a front sight and also include full length side and bottom rails. Knight's Armament specifically integrated these components to equip the upper receiver with the best modular advantages while also ensuring the least amount of interference with the rest of the components.