Are you having trouble finding a 300 blackout bcg (bolt carrier group)? Are you new to shooting 300 blackout? Does 300 blackout use 5.56 BCG? Today we’re discussing 300 blackout bolt carrier group options.

Don’t be upset – if you’re new to rifles or the 300 blackout, you may not know this. You can actually use a .223/5.56 BCG to put your 300 blackout round into the rifle chamber. The best overall 300 blackout BCG is the HM Defense AR15 BOLT CARRIER GROUP.

The Best 300 blackout BCG available right now

We’ve created a list of the best quality and most affordable 300 blackout bolt carrier groups available

  1. HM Defense AR15 BOLT CARRIER GROUP – Best Overall 300 Blackout BCG
  2. CMMG 5.56 M16 Bolt Carrier 55BA419 – Best MilSpec 300 Blackout BCG
  3. Spikes AR15 NIB Bolt Carrier Group – Best Nickel Boron 300 Blackout BCG
  4. CMC Enhanced MIL-Spec Nitride BCG – Best Nitride 300 Blackout BCG

#1. HM Defense AR15 Bolt Carrier Group

Check Current Price | Best Overall 300 Blackout BCG

Pro’s and Con’s


  • Good value for any budget or high performance 300 blackout rifle
  • Designed and manufactured by a combat veteran owned company
  • Compatible with 5.56 NATO, .223 Rem, and 300 AAC


  • You may not have heard of this company
  • Low quantity available
  • Not the cheapest BCG on market

Our experience with the HM Defense AR15 Bolt Carrier Group

Looking at the bolt, it’s your standard AR15 bolt carrier group. It’s compatible with the “big 3” AR15 calibers, made from 9310 steel, and features a black nitride finish.

As compared to a phosphate coated BCG, you’ll be able to rely on this BCG when it counts. It is MilSpec quality and a great addition to your next AR-15 rifle.

Some drawbacks however is its price. You can find cheaper models right now – we mention one phosphate BCG below that retails at only $123.99. While that might be alright, I’d like to buy once and not buy again for a long time.

Depending on how often you shoot, you might want to find something cheaper or even on clearance. Worth Firearms is offering this BCG at $140.99 while the MSRP is $175.00. Because quantities are low, you might miss out on this opportunity.

#2. CMMG 5.56 M16 Bolt Carrier Group

Check Current Price | Best MilSpec 300 Blackout BCG


Pro’s and Con’s


  • Mil-Spec M16 5.56 NATO BCG (works with 300 blackout)
  • Steel bolt
  • Phosphate finish
  • Sturdy firing pin


  • High cost for a phosphate BCG

Our experience with the CMMG 5.56 M16 Bolt Carrier Group

This is a great drop-in solution as a replacement bolt for your 300 blackout. It’s components are mil-spec – so you know it must meet the quality and reliability standards of the US military.

I’ve seen both nitride and phosphate finished bolts claiming they’re mil-spec. If you’re looking to get a “clone” build going – you will need to dig deeper on which finish the M16 or M4 came with.

We feel the phosphate finish is a lesser finish compared to the nitride BCG’s. The porous feeling makes it seem harder to clean and absorbs more carbon.

There are definitely cheaper options than this bolt – but being a drop in replacement for the M16 makes us feel like this is the top mil-spec BCG available right now.

#3. Spikes AR15 NIB Bolt Carrier Group

Check Current Price | Best Nickel Boron 300 Blackout BCG

Pro’s and Con’s


  • Laser engraved Spike’s Tactical
  • Nickel Boron Coating
  • Special Color: Silver
  • High quality


  • Expensive
  • Aesthetic of a shiny BCG may not be your thing

Our experience with the Best Nickel Boron 300 Blackout BCG

This mil-spec nickel boron BCG is a true drop-in replacement for any AR-15 build – .223, 5.56, and 300 blackout. It’s also a drop in for the M16 spec rifle.

While this is the ultimate BCG for reliability, durability, and ease of cleaning, you’re looking at a big price tag. This would definitely be more than enough for the weekend shooter. The nickel boron finish will make the cleanup after each range session go by faster.

#4. CMC Enhanced MIL-Spec Nitride AR15 BCG

Check Current Price | Best Nitride 300 Blackout BCG

Pro’s and Con’s


  • Long term reliability
  • Durable construction
  • Mil-Spec
  • Nitride finish


  • Expensive compared to lesser quality finishes

Our experience with (name)

The CMC Enhanced MIL-Spec Nitride AR15 BCG performed surprisingly well with our short barreled rifle. The decrease in points of contact results in less friction. The increase in mass produces proper gas pressure, which improves extraction while shooting an SBR or suppressed.

The nitride finish will make cleaning easier than phosphate BCG.

This may not be the bolt for some shooters. While great quality, it’s easily a bit overkill for the once in a while shooter.

How to choose the best 300 blackout BCG?

You have a few options when it comes to your 300 blackout bolt carrier group. While there aren’t any specific 300 blackout bolt carrier groups, we do know that .223 and 5.56 BCG’s work in a 300 blackout build.

While many factors affect the overall function of a rifle and it’s BCG – the barrel length is not one of them.

Your most important factors to consider are:

  • Cost
  • Finish
  • Manufacturer


We think this is the most important one to start with. Many people have a budget when building a rifle.

A low end BCG will run you between $120 – $275. At the higher priced end, you’re looking at higher quality finishes for enhanced reliability, quality, and durability.

Our least expensive 300 blackout bolt carrier goup is the Fail Zero Bolt Carrier Group, at $123.99.

Our most expensive 300 blackout bolt carrier group is the Lantac Evanced Bolt Carrier Group, at $261.99.

Read more about Aero Precision BCG’s.


We’ve mentioned finish differences in past posts and why one is superior to the other. As a quick refresher, there are 3 primary finishes your bolt carrier group will come in:

  • Phosphate
  • Nitride
  • Nickel Boron


Many manufacturers (we’d dare say most of them) have tight manufacturing standards and are going to produce a quality product. We think the finish and cost are far more important than the manufacturer.

These bolts didn’t advertise magnetic particle testing but we still feel the QA process when manufactured were second to none.

Rating criteria

We rated the above 300 blackout BCG options by their:


  • Price
  • Finish
  • Durability.

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