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Best Low Mass BCG for the Money Comments Off on Best Low Mass BCG for the Money

As part of a lightweight AR build in 5.56 NATO, I decided to give the NBS Lightweight Bolt Carrier Group a try. NBS (stands for No Bullshit) is the “house” brand for which is a great online firearms parts and accessories retailer. According to their website, NBS products are either procured from “reputable OEMs (Original Equipment Manufacturers) or are assembled in-house using name brand parts and components. All NBS products are backed by the NBS Limited Lifetime Warranty.”

Why Choose NBS Over More Expensive Brand Name Low Mass BCGs?

First, I wanted a low mass BCG that was not too light…something in the 8.5 to 9 oz range. This would save a few ounces over a full mass BCG while not compromising reliability by going with an ultra low mass BCG made from titanium or aluminum.

Second, pricing for the NBS lightweight BCG, when on sale, has been as low as $69.95 plus shipping. Now, I would love to get a JP Low Mass BCG, but at $350, I simply could not justify the cost.

Third, I have purchased a few NBS “full mass” bolt carrier groups before and have never had any issues with them.

And lastly, stands behind everything they sell, so if there is a problem, they quickly address it.

NBS Steel Low Mass BCG with Lantac Cam Pin
NBS Steel Low Mass BCG with Lantac Dome Cam Pin

Features of the NBS Lightweight Bolt Carrier Group

  • .223/5.56 NATO
  • Black nitride finish
  • Magnetic particle inspected
  • 9310 steel bolt
  • Case hardened 8620 tool steel heat treated carrier
  • Staked gas key
  • Grade 8 fasteners
  • 4140 steel cam pin
  • Shot peened tool steel extractor
  • Weight: 8.875 oz (according to my scale)

Since I had an extra Lantac domed cam pin laying around, I ended up using it in the NBS BCG. There is actually nothing wrong with the original cam pin that came with the NBS BCG.

NBS Lightweight BCG with Lantac Cam Pin
NBS Lightweight BCG with Lantac Dome Cam Pin


MSRP is $139.95 but, I have seen it on sale for as low as $69.95.

General Impressions

Machining is good. The Nitride finish is slick, but does show signs of wear at common wear points such as the carrier rails, after a few trips to the range. Not a big deal, but just something I noticed.

Gas key staking was not done as well as I would have liked, but I believe it should be fine.

NBS Lightweight BCG Gas Key Staking

At the Range

Having shot approximately 160 rounds of 5.56 NATO 55 gr FMJ (M193), suppressed with a YHM Turbo and an Aero Precision adjustable gas block dialed in, using a Balios Lite build, I experienced no malfunctions whatsoever. I also use the NBS low mass BCG in a Wilson Combat billet receiver build.

Final Thoughts

If you are looking for a relatively lightweight, good quality BCG that won’t break the bank, you may want to consider the NBS Lightweight Bolt Carrier Group in black nitride. I really find it to be the best low mass BCG for the money.


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