• Caliber: 5.56 NATO / .223 Remington
  • Chamber: 5.56 NATO
  • Finish: NiB-X Nickel Boron Coating
  • Upper Receiver: 7075-T6 Billet or Forged aluminum
  • Handguard: 12-Inch or 15-Inch M-LOK NiB-X Coated 6061-T6 Aluminum
  • M4 Feed Ramps: Yes
  • Muzzle Device: NiB-X Nickel Boron coated, Primary Weapons System PWS FSC 5.56 Compensator
  • Barrel: 16” match grade 4150 Steel with Nitromet finish Barrel
  • Muzzle Thread Pattern: 1/2"-28
  • Gas Block: NiB-X .750" Low Profile Gas Block
  • Gas Tube: Carbine-Length Nitromet Gas Tube
  • Bolt Carrier Group: WMD Guns NiB-X Bolt Carrier Group
  • Charging Handle: WMD Guns 7075 Billet Aluminum NiB-X Coated Charging Handle


  • Weight: 4 lbs 7.2 oz.
  • Length: ~25"


  • AR-15 lower receivers


If you ever start down the custom gun trail, it’s hard to return. Sure, it’s no problem to switch out a stock or safety selector. However, when it comes to a complete upper receiver, things get a little trickier. DIY projects are fun until they get away from you. Picking up a complete WMD NiB-X upper could be the reasonable cure for your upgrade bug.

One-Piece At A Time

The old Johnny Cash song made this sound like fun. But, depending on your level of expertise and available time, it can be a nightmare. If you are lucky enough to select the right parts, the cost of ordering individual pieces adds up. Perhaps the parts you want are on backorder. How long is it going to take to amass everything you need? The time involved alone is a headache. That's where the WMD NiB-X upper receiver comes into play. Scroll back up, click, and your complete upper is on the way.

Hire A Professional

WMD’s engineers select the proper components you need inside their NiB-X upper receiver. You don’t need any fancy armorers tools or even a vise. The WMD NiB-X upper fits on any Mil-Spec lower. That’s the easy part. WMD starts with a top-grade 7075 T6 aluminum billet. Adding a match-grade barrel and precision machine work bring you an upper that looks as good as it shoots. WMD wraps that beautiful barrel in an aluminum Key Mod or M-LOK free-floating rail. Of course, you get a full-length 1913 Picatinny section on the top. If you can’t find a spot to mount something on this rail, you don’t need it. Finally, every outer surface gets the extreme NiB-X proprietary finish. This upper is slick, wear-resistant, and it lives to please.

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