FN M16A4 5.56 NATO 20" Rifle - AR-15 Platform, Rifle-Length Gas, Quad-Rail, A2 Front Sight, PMAG
Built by FN America, this M16A4 pairs a 20-inch, FN-stamped 5.56 NATO 1/7 barrel with a rifle-length gas system and a flat-top, T-marked upper receiver. It features FN Columbia, SC receiver markings with MFR/CAGE code 3S679 and a UID/asset label on the magwell. The rifle includes a fixed A2 front sight base with bayonet lug, a two-piece quad-rail with Knight's Armament rail covers, a detachable rear iron sight, and a vertical foregrip. Overall condition is excellent.
Condition
Overall Condition: Excellent condition, showing only faint signs of any prior use or handling.
Bore Condition: Excellent - Clean, mirror finish, no signs of wear.
Rifling: Excellent - Sharp lands and grooves.
Specific Condition Notes: Aside from a few mild scuffs, this rifle is in great shape.
What's Included
- 1x 30-round Magpul PMAG polymer magazine
- Knight's Armament rail covers with 1S002 markings (installed)
- Vertical foregrip (installed)
- Detachable rear iron sight (installed)
This M16A4 is configured on the AR-15 platform with a flat-top upper receiver featuring T-marked Picatinny rail positions (T4–T12 visible). The receiver is equipped with a forward assist, case deflector, and ejection-port cover, and is finished in a matte hard-anodized coating. Factory markings include FN Columbia, SC and the MFR/CAGE code 3S679, plus a UID/asset label with QR code on the magwell.
The 20-inch steel barrel is stamped "5.56 NATO 1/7" with FN marking and uses a rifle-length gas system for traditional M16A4 configuration. It is threaded and fitted with an A2 flash hider. The front sight is a fixed A2 sight base with bayonet lug and sling swivel, paired with the included detachable rear iron sight.
The rifle wears a two-piece quad-rail handguard, providing rail space for accessories. Knight's Armament rail covers marked 1S002 are installed. Controls include a manual safety, with three-position SAFE/SEMI/AUTO selector legends on both sides. The upper is optics-ready via the flat top rail; the included rear sight mounts to the top rail.
Furniture is durable and straightforward: a fixed polymer stock with a 13.5-inch length of pull and an A2 pistol grip. A vertical foregrip is installed on the quad-rail for added control. The overall finish is a consistent matte hard-anodized tone across the receiver set.