Knight's Armament SR-15 E3 Mod 2 5.56 NATO 16" Rifle – URX 4, Ambidextrous Controls, KAC Micro Sights, QDC 3-Prong Flash Hider
The Knight's Armament SR-15 E3 Mod 2 stands out with its E3 bolt architecture, proprietary mid-length gas system with a locking-ring gas block, and a 16-inch hammer-forged, chrome-lined barrel with a 1:7 twist. It comes outfitted with a KAC URX 4 free-float handguard featuring a continuous 12 o'clock rail and M-LOK slots, fully ambidextrous lower controls, and KAC Micro folding sights with a 200–600 m rear. This example also features a factory KAC QDC-compatible 3-prong flash hider and clear factory markings including "STONER RIFLE," the Knight's crest, and "MOD 2" on the receiver.
Condition
Overall Condition: Very good condition, showing only light, superficial signs of prior handling or use.
Bore Overall Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: Minor surface scratches and small finish blemishes are present from prior handling and use.
What’s Included
- 2x 30-round Magpul PMAG Gen M3 polymer magazines
- Vice block (gunsmithing tool)
- Rail adapter (mount)
- Packaging for a Magpul PMAG Gen M3 Window magazine
The 16-inch barrel is hammer-forged and chrome-lined, with a 1:7 twist and a threaded muzzle capped by a KAC QDC-compatible 3-prong flash hider. This configuration supports 5.56 NATO and uses a direct impingement system paired with Knight's proprietary mid-length gas system and a locking-ring gas block.
The KAC URX 4 free-float handguard provides a continuous 12 o'clock Picatinny rail with M-LOK slots for accessory placement. A built-in QD sling socket on the handguard adds sling attachment flexibility while keeping the profile streamlined.
Controls are fully ambidextrous, including the safety selector, bolt catch/release, and magazine release, and the rifle includes a KAC ambidextrous charging handle. The lower is outfitted with a six-position collapsible polymer stock and a Magpul polymer pistol grip for a familiar AR-15 ergonomics package.