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(Consignment B) Knights Armament SR15 E3 Mod2 M-Lok 16" Barrel 5.56x45mm MFG# 10305 UPC# 819064015598

Knights Armament SR15 E3 Mod2 M-Lok 16" Barrel 5.56x45mm MFG # 31900 Noveske Upper LMT Stock LMT Bolt Carrier Heavy Barrel -Fired to test function and grouping, otherwise brand new.
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Knights Armament SR15 E3 Mod2 M-Lok 16" Barrel 5.56x45mm MFG # 31900

The SR15 E3 Mod2 series' 5.56mm Nato barrel is manufactured for military grade durability, and is free-floated inside a URX4 M-LOK handguard. An improved E3 round-lug bolt design both enhances function and increases bolt life far beyond the industry standard. The ambidextrous bolt release, selector lever, and magazine release offers left-handed users the ergonomic advantages inherent to AR15-based controls. The drop-in two-stage trigger severs double duty as an aid to precision marksmanship while enabling surgical speed shooting at close range. The 5.56mm 3-Prong Flash Eliminator interferes with propellant gas combustion forward of the muzzle to significantly reduce flash signature, will not ring upon firing or when struck, and is compatible with the Knights line of 5.56mm QDC Signature Reduction Devices.


  • Barrel: 16"/40cm 1:7 Twist, Hammer Forged, Chrome Lined
  • Caliber: 5.56x45mm/.223
  • Weight: 6.55lbs/2.97kg
  • Length: 33.5"/85.09cm to 36.5"/92.7cm

E3 Enhanced Bolt:

  • The E3 Enhanced Bolt from Knights Armament features a number of components designed to make this bolt the most durable and reliable bolt available. It is a proprietary bolt specifically deisgned for their SR15 and 16 models. The E3 Bolt boasts several features that add to the its overall performance such as the enlarged bolt face, rounded lugs, reduced cam pin, and proprietary extractor and firing pin designs.
  • This E3 Bolt is manufactured with an enlarged bolt face that provides more positive engagement in the chamber and lugs which are rounded to help reduce chipping, cracking and snapping. This strengthened design helps to increase the life of the bolt and ensure a proper seating each time the weapon cycles.
  • The E3 Bolt's extractor design is also a unique achievement that helps to provide an extremely reliable component. It's shaped like a rounded "T" and sometimes referred to as a "butterfly" shape. The pivot point of the extractor is shifted forward to help balance out the extractor and apply constant pressure on the shell which reduces cases of extraction failures. Another stronge feature of the unique design of this extractor is the use of two full size extractor springs, as opposed to the standard micro spring. This allows for a reduction of relative compression while the extractor is in motion and provides a failsafe in case one spring fails. The bolt will continue to function properly and afford a user the opportunity to continue with their mission or firing schedule.
  • The E3 Bolt is designed with a thinner Cam Pin and Firing Pin whose overall size has been reduced. The thinner Cam Pin allows for a thicker bolt web which is a common failure point in normal bolts. The reduction of the Firing Pin size is to accommodate the thinner Cam Pin.
  • The full capabilities of the E3 Bolt are realized when exposed to full auto or extremely high cyclic firing rates yet the bolt performs gracefully under casual firing conditions. This component was designed to be exposed to the most stressful and unrelenting conditions and exceed expectations for durability and service life.

Hammer Forging:

  • Knights Armament employs a hammer-forging process on a number of there barrels and chambers, which serves to increase the quality of their interior finish, as well as increasing the durability and life of the barrel. These barrels are then Chrome-lined to further the lifespan of the barrel and increase its resistance to fouling and corrosion.
  • The first step is to take a drilled barrel and hone the interior to a fine, clean finish. The barrel is then placed onto a mandrel with the rifling pattern ground in relief across it. This setup is then placed between opposing power hammers which literally hammer the barrel onto the pattern found on the mandrel. The barrel setup is rotated and the hammers continue to forge the barrel into its final shape. Once they complete this process, the barrels are heat treated in order to relieve the inherent stress created during this process.
  • The Chroming process is applied after the Hammer Forging. At this point the interior of the barrel is basically lined with a layer of chrome and bonded to the forged steel. Chrome is approximately twice as hard as standard 4150 steel and also resists the lead and powder that bare steel will normally absorb into its pores. This allows the barrel to be exposed to the higher temperatures and pressures of high firing schedules while still maintaining accuracy, durability and reliability. The end result is a denser, stronger barrel that will endure a higher round life than a Standard Stainless Steel or Chrome Moly barrel.

Ambidextrous Controls:

  • Knights Armament designed this system to give shooters the maximum amount of options in their controls. Under this design all of the weapon's major controls can be acessed from either side of the lower receiver. Left-handed shooters see the immediate benefits of being able to access the weapon's controls in a more intuitive manner; however, there are a number of other benefits that right-handed shooters will enjoy under this system.
  • Competition shooters benefit from these controls from the increase of speed that is achieved through components such as the right-size bolt catch. Trainers enjoy the variety of options because they can watch their trainee from either side of the weapon and even manipulate the weapon's controls from the non-operating side. KAC has also introduced modifications to the design such as the scalloped safety selector switch. This allows a lower profile for the selector swtich on the non-operating side of the receiver which helps to relieve any interference between the switch and a shooter's glove or hand. For the maximum amount of configuration and operation options, Knights Ambidextrous Controls offer a sure solution.

Two-Stage Match Trigger:

  • All of the weapons available from Knights Armament come equipped with a 4.5lb, 2-Stage Match Trigger. This type of trigger mechanism uses a system where, during the rearward squeeze of a trigger, it cycles through two stages of resistance.
  • The first stage is a "no-poundage" stage where hardly any resistance is felt during the rear-ward squeeze. There is a center point at which point resistance is felt and the second stage of the trigger begins. At this point, 4.5 pounds of force is required to squeeze the trigger through the second stage and cause the weapon to cycle.
  • Their 2-stage trigger is meant to inform a shooter of exactly where their weapon is going to fire. This bolsters a Firer's confidence and can also assist in reducing trigger jerk, thereby increasing accuracy. The 4.5lb 2-Stage Trigger fron Knights Armament is a highly calibrated and smooth component that is sure to be a welcome additon to any setup.

Quick Detach Coupler:

  • The Quick Detach Coupler (QDC) line of Sound Suppressors and Muzzle Devices are proprietary items designed for secure interoperability. The coupling device itself consists of multiple ball bearings arrayed in a circular pattern which fit into sockets specifically machined into various muzzle devices to accept the QDC. The bearings are aligned with the sockets by way of a V-shaped notch that seats the device onto an index pin. Once aligned, a simple twist of the outer retaining ring locks the device securely into place.
  • This system was developed to provide fast and easy operation and interoperability between weapons and suppressors. Knights QDC line of sound suppressors all feature this method of attachment. Various muzzle devices, such as the QDC Flash Suppressors and the MAMS muzzle break, also feature the QDC pockets to accept sound suppressors equipped with this coupling device. Secure interoperability and intelligent, efficient design are the intended goals of this quick and easy technology.


  • M-LOK is a modular locking accessory mounting system that is a direct attachment method for hard mounting accessories to a negative space mounting point. The M-LOk attachment system allows the user to put mounting rails only where they were needed, as opposed to covering the entire surface with mounting rails, which are then covered with panels. The system also allows direct mounting of accessories, such as fore-grips and flashlights, with no rail interface needed.
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