Expo Arms 5.56 NATO Complete M16-Cut AR-15 Bolt Carrier Group - Nitride

Manufactured by Expo Arms
2 Reviews


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The Expo Arms Bolt Carrier Group is a great choice for any build. This drop-in AR-15 BCG features a corrosion resistant salt bath nitride finish, MIL-SPEC dimensions, and a magnetic particle inspected carpenter 158 steel bolt. Crafted from domestically sourced 8620 steel, the M16 cut carrier includes a gas key fastened by properly staked grade 8 screws. Made in the U.S.A. and covered by a lifetime warranty, you can count on this BCG for a lifetime of service.

  • .233/5.56 NATO
  • Salt bath nitride finish
  • M16 cut
  • Aircraft quality 8620 steel carrier
  • 4130 steel gas key
  • Properly staked grade 8 gas key screws
  • Carpenter 158 steel bolt
  • 4140 steel extractor
  • MIL-SPEC O-ring
  • MIL-SPEC gas rings
  • 4140 steel cam pin
  • 8740 steel firing pin with hard chrome finish
  • Magnetic particle inspected
  • Lifetime warranty
  • Proudly made in the U.S.A.


Bolt FinishManganese Phosphate
Bolt MaterialCarpenter 158 Steel
BrandExpo Arms
Caliber Gauge5.56 NATO
Carrier FinishSalt Bath Nitride
Carrier Material8620 Carpenter Steel
Carrier StyleM16 Bolt Carrier
High Pressure TestedUntested
Magnetic Particle InspectMagnetic Particle Inspected

Ratings & Reviews

2 reviews

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I'm happy.

by -

Will update if I have any issues but upon initial inspection this is a very nice BCG. Mine has absolutely no tool maks, the nitride is smooth and looks really nice. BCG is in spec compared to other BCG's I have. I'm happy with this purchase.

Awsome sales experience and great product

by -

This item was an add on option to the Bear Creek Arsenal 16" Mlok 300 AAC Blackout upper assembly I purchased to add functionality to my home built 5.56mm AR. This is a melonited (Nitrided) BCG. After a day at the range, I came home and cleaned the upper. The melonite finish makes cleaning a very easy task. This BCG functioned flawlessly. I'm really impressed with the speed that Primary Arms had the upper with options delivered on my doorstep only 3 days after I ordered it.Great product at a great price. Thanks Primary Arms!