WMD 5.56 AR-15 Bolt Carrier Group Without Hammer - NiB-X Finish

Manufactured by WMD Guns
Manufactured by WMD Guns
48 Reviews
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The WMD BCG is precisely machined from high-grade steel to M16 specs before receiving WMD Gun's proprietary NiB-X nickel boron coating. This coating results in super-smooth action, extreme corrosion resistance, and a harder-than-chrome surface that prevents carbon fouling from adhering, making this an ideal choice for any one who does high-volume shooting. This set features a polished finish and does not include the hammer. If you are looking for a long lasting AR-15 bolt carrier group, the NiB-X BCG is guaranteed to keep your rifle running reliably for years to come.

  • Proprietary Nickel Boron coating
  • Extremely durable and easy to clean
  • Slick surface makes for an extremely smooth action
  • Polished finish
  • M16 cut
  • Does not include hammer
  • Carrier Steel: 8620 and heat treated
  • Bolt Steel: Carpenter 158 and heat treated
  • Firing Pin: Hardened and chromed
  • Gas Key: Hardened and staked per military standards

WMD Guns has established a reputation of excellence based on extensive firearms and defense industry experience, plating expertise, and gunsmithing capabilities. They are innovators in nickel boron products for the firearms industry and the sole source of the NiB-X nickel boron coating process.
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Bolt FinishNickel Boron
Bolt MaterialCarpenter 158 Steel
BrandWMD Guns
Caliber Gauge5.56 NATO
Carrier FinishNickel Boron
Carrier Material8620 Carpenter Steel
Carrier StyleM16 Bolt Carrier
High Pressure TestedUntested
Magnetic Particle InspectMagnetic Particle Inspected
Weight12 Oz
California Prop 65 warning

 WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information go to www.P65Warnings.ca.gov.

Ratings & Reviews

48 reviews


Hope it gets better.


After researching nickel boron BCGs, I decided to go with this one. The finish is perfect. No machining marks and smooth. Cleaned BCG and applied a light coat of oil. Fired 20 rounds last night and didn't clean it. Tonight, the caming action of the bolt in the carrier was very stiff. Noticably harder to charge the rifle. Disassembled, cleaned, and lubed bolt and it works better. I was firing factory new Hornaday ammo. Hope it gets better than this.

At build


Amazing BCG super finish and quality



Awesome bcg! One of my favorites!

Best BCG


Best I've used in a while, easy to clean however once used the finish is still bright but darker and took on a gold color instead of the silver.

Quality BCG


Compared the NIB-X to a bunch of other Nickel boron BCG's for my gas impingement AR and decided on it over the rest. Received it, cleaned it thoroughly and once it was clean it's literally like it's oiled! I still will run it with a light coat of Slip 2000 EWL! UPDATE: Took it to the range last Saturday and ran 60rds through it with no issues. Got home and wasnt impressed with how it cleaned up! My P.O.F rifle has a NP3 coated BCG and is a true wipe off BCG. IT is a piston rifle so it runs cleaner and cooler but was a little disappointed in the companies claim to simply wipe off.

Outstanding Quality!


Couldn't be more pleased! The finish is extremely smooth. Carbon fouling brushes off. This product is a must have item for DGI rifle!



Excellent, Outstanding! Both the product and Primary Arms are superb!

Very nice BCG!!


First off, I want to thank Primary Arms for their superb customer service. They also process and ship orders faster than any other company I know of. Okay, so now to the WMD BCG. This is the first NiB-X BCG I have ever owned, so I cannot compare this to any other. I was amazed at how slick it feels right out of the bag. I also examined it for fit and finish. I did not notice any burrs or sharp edges anywhere. The machining is excellent and I can see that their quality control is on par with higher end BCGs that I've owned in the past. As of writing this, I have put 300+ rounds without issues. I purchased the "full-auto" version and it works and runs flawlessly through my Spike's Enhanced AR15. I would have to give this purchase 5 stars for both product and PA's fast shipping. If your thinking of purchasing this, don't hesitate.



Great product and service

Great product


Great product the best service.This is my second WMD Nib-X bolt carrier. I wish I had them in all my AR's. The fit and function is perfect and the Nib-X finish lives up to its claims.