• 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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Reviews (2)

  • Wow

    Posted by Richard Lopo on 26th Dec 2021

    I bought this upper for my son for Christmas we just took it to the range and OMG! This upper is not the most expensive I think $650.00 around that I have uppers I have spent over a grand. This upper felt like it was stuffed full of butter the ammo just glided out it was so smooth. We let 4 different people shoot it at the range amd they couldn't believe how nice and smooth this gun was shooting. O and all of our groupings where less then a quarter of a inch. This is a bad ass upper!!! Buy it

  • WMD Nibx upper receiver group

    Posted by Steven on 29th Sep 2020

    I was greatly excited to receive my upper. Once my creation was finished, it ran like a charm. I liked it so much that I purchased a second one and started another build. Several gunsmiths were greatly impressed.

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