Expo Arms 5.56 NATO Complete MIL-SPEC M16 / AR-15 Bolt Carrier Group - Phosphate

Manufactured by Expo Arms
Manufactured by Expo Arms
36 Reviews
$111.96 $139.95

In Stock

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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 tough manganese phosphate 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
  • Hard chromed bore and gas key
  • Manganese Phosphate finish
  • M16 cut
  • Aircraft quality 8620 steel carrier
  • 4130 steel gas key
  • Properly staked grade 8 gas key screws
  • Carpenter 158 steel bolt
  • 4340 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.
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Bolt FinishManganese Phosphate
Bolt MaterialCarpenter 158 Steel
BrandExpo Arms
Caliber Gauge5.56 NATO
Carrier StyleM16 Bolt Carrier
High Pressure TestedHigh Pressure Tested
Magnetic Particle InspectMagnetic Particle Inspected
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

36 reviews

  • 3 stars
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4K Rounds and counting.

by -

Waited to review this item. Arrived quick within a weeks period. One it came in I decided to right away change the extractor spring and o-ring to the BCM enhanced set. Outside of all that she’s been down 3k of steel and 1k of brass. So far no signs of wear on it.

Great premium BCG

by -

This appears to be a very high quality BCG made from the premier manufacturer in the industry. I bought a new Colt 6920 SOCOM late last year, and the BCG that came with it didn't have a "C" or "MPC" on it. But it did look EXACTLY like this one from EXPO. Both also have aggressive gas key staking. I believe they are made by the same company. Meaning it's right there with BCM and SOLGW BCG's.

good to go

by -

Very nice finish, machining and construction. All the interior bore surfaces are extremely smooth. Cycled brass and steel case ammo just fine. Nice ejection pattern. All components are wearing in nicely. I am very pleased

Tier 1 BCG


Awesome BCG. It seems as it is the same quality as some tier 1 BCGs in the game. Wouldn't hesitate to buy another one.

I dig it.


Good specs, looks good, works well, no problems.

Quality BCG from Expo Arms


Whether you need something as simple as a length of rail or a chromed bolt carrier group for better, more reliable performance, Expo Arms has the AR-15 part you need priced within your budget.

Excellent Value


These appear to be from Microbest, same place BCM, SOLGW, DD, and many more high end milspec BCG's are manufactured. The pronounced chrome lining coming out from the bolt shoulder of the carrier (opening of the carrier where the bolt goes in) is a dead giveaway for Microbest. The bolt is stamped MP from the manufacturer, looks exactly like the same font as SOLGW. The firing pin appears to be polished, just like BCM's. The staking is strong and pronounced, no YFS fasteners, these look to be grade 8. I understand Microbest just makes them, each manufacturer who sources them has their own standards for QC which helps give the BCG's from these manufacturers their reputation, but these Expo's are coming from as reputable a place as possible. Everything looks solid, and the price is excellent especially for right now (3/21). Hopefully you are reading this in the future and quality components are much more plentiful and accessible, but right now, this seems like the best value around.

High End BCG- at a low price


Rest assured, you are getting a great mil spec carrier when you get the Expo. Here is why: As I do with all BCGs when they arrive, I take them apart and inspect everything (and do some measuring). As I did this one, I noticed that it all looked very familiar. I grabbed a new BCM bcg, broke it down, and compared everything. Now, I'm not a fanboy who only uses BCM or anything, but they make a darn good mil spec product. With that said, If BCM didn't put their name on everything, I absolutely would not have been able to tell the two apart. The design and tooling of the carriers was exactly the same. The bolt is of the same design and tooling, and had the exact same "spotted coloring" that BCM bolts usually have. The only difference I found, as expected, was the extractor spring was simply mil spec (BCM upgrades theirs to Sprinco in house). I ran a few mags through it today, and it ran flawlessly. I'm impressed.



I’ve been in the Ar15 for a little while now . I’m also an an armorer who’s been fortunate to be taught by some of the best in the business. The Expo BCG is what you would expect if you had bought a BCM or SOLGW BCG . It’s my top pick for all my builds because of its cost and it’s a BCG that’s made for hard core use. You can’t beat it for the price and quality. I will be buying more 7 more just to keep them in hand for future builds.

Expo BCG


Very impressed with P.A. received it in 4 days w/ my charging handle. STILL WAITING! for my upper from another co. Will follow up later w/ a review after I put Some rounds thur it