Tag Archives: BCG

Primary Arms Has WMD NiB-X AR 5.56 Bolt Carrier Groups On Sale

Folks, Primary Arms has WMD Nickel Boron bolt carrier groups (BCGs) on sale and in stock! These are my favorite AR-15 BCGs and I always recommend them. Note, they make a .308 BCG but I haven’t tried one yet.

Their Nickel Boron coating is excellent the lubricity is superb – even without any oil they move very freely. They also hold up great as well.

The following specs are from WMD’s website:

  • Bolt – Carpenter 158 heat-treated, shot peened and magnetic particle inspected.  Manufactured to government drawings.  Milspec gas rings. NiB-X coated (40% more wear-resistant than chrome).
  • Extractor – Manufactured, heat treated, and hardened per government drawings.  Black extractor buffer and heavy-duty spring. NiB-X coated.
  • Firing Pin – Manufactured, heat-treated, hardened, chromed and certified per government drawings.
  • Carrier – AR-15 or M16 style (heavy weight), 8620 material, heat treated and case hardened.  Manufacturing tolerances on inside diameters tightly controlled.  NiB-X coated for durability and ease of cleaning.
  • Gas Key – Hardened to USGI Specifications and attached using knurled grade 8 hardened fasteners. NiB-X coated.  Staked per military specifications. The knurled screw heads further enhance the effectiveness of the staking.
  • Cam pin – Manufactured, heat treated, hardened and certified per Government drawings.  NiB-X Coated.
  • Hammer – Manufactured, heat treated, hardened and certified per government drawings.  NiB-X Coated.  Can be semi-auto or full-auto.

The photo above is of the WMD BCG in my 10.5″ AR pistol. Here are a few more photos for you as well.

The WMD BCG is at the top and a regular PSA BCG is at the bottom.

So if you are shopping for a BCG – definitely check these out – click here to open the Primary Arms page! I hope this helps you out – these really are my favorite BCGs for the AR-15.


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