The BCG (bolt carrier group) is the beating heart of any rifle. The revered AR-15 rifle can be easily converted into a 9mm caliber rifle with minimal component changes.
One such important component for this change is the 9mm BCG. But simply picking any random BCG doesn’t create a flawless AR. Check out this detailed discussion to get better insights about this topic, and also take a look at the best 9mm BCGs that are prevalent today.
At a Glance: Our Top Picks for 9mm BCG
- OUR TOP PICK: Brownells - AR-15 Brownells 9mm Bolt Carrier Group
- RUNNER-UP: Faxon Firearms - AR-15 9mm Bolt Carrier Group
- BEST BUDGET OPTION: J P Enterprises - AR-15/M16 9mm Bolt Carrier Group
Comparison of the Best 9mm Bolt Carrier Groups
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Factors to Consider Before Buying a BCG For Your AR Build
A BCG is the most important component inside your AR rifle. This is the part that works the most and is responsible for the proper operation of your rifle. Building a 9mm AR is not that tough. Until you abide by a few considerations in your mind.
This Section Written By:
Ankit Kumar
Expert Author
Ankit Kumar is an engineer turned writer who specializes in topics related to firearms, gun safety and weapon tech. His passion towards enrolling in the Army drifted his interest towards light and heavy firearms. He’s a qualified competitive air rifle shooter and an avid nature lover. His other areas of expertise include survival, prepping and firearms/ammo storage. When he’s not writing, he’s either learning a new skill, trekking or enjoying a long drive.
Strength and Inspection
BCG’s are mostly manufactured from Carpenter 158 steel, 9310 steel, or 8620 steel. There are a lot of material variations out there. Durability is directly proportional to longevity. Of course, factors like weight and cost will also come into play here. So make a balanced decision according to your tastes.
Apart from that, buying a BCG that has been MPI (Magnetic Particle Inspection) and HPT (High Pressure Tested) further confirms that it is strong enough.
The Best Coating to Rely Upon
Nitride, NiB, phosphate, or TiN. These are the most common coatings available for BCGs. Each of them has its own advantages. For example, nickel boron (NiB) coated BCG is super smooth and very easy to clean. This also means that they do not allow too much grime to deposit over them.
A Titanium Nitride (TiN) coating is one of the best you can ask for your BCG. It appears golden and offers easy cleaning benefits along with a very tough and lasting coating. You’ll often find TiN coated BCG in high-end AR rifles.
Faxon Firearms - AR-15 9mm Bolt Carrier GroupPhosphate and Nitride are the most economical and common coatings you’ll find on BCG’s. Where phosphate is the mil-spec.
Aftermarket Parts Compatibility
The 9mm BCG is obviously different in size than the regular .223/5.56 AR-15 BCG. But since many components are used interchangeably for quick swapping of calibers. It is important to note that aftermarket triggers designed for the .223/5.56 may not work properly with the 9mm setup.
So always ensure that you get a trigger that has been specified to be used with 9mm AR rifles when using aftermarket triggers. Additionally, components like magazines, magwell flare, and Colt or Glock compatible upper and BCG are also important considerations before creating the AR9 build.
On a side note, make sure the bolt works with ramped barrels. If you already have one.
Review of the Best 9mm BCGs
The following is a list of the five best 9mm BCGs currently on the market. If your AR-15 9mm rifle needs an upgrade or if you’re building one from scratch, one of these five will end up being yours to own. As you look through each one, pay attention to the features and functions.
These might end up matching your list of what to look for in a BCG. It doesn’t have to be a perfect match, but “close enough” is better than nothing. Now, let’s kick off this list by unveiling our “best overall” choice:
Best Overall:
Brownells 9mm Bolt Carrier Group
Pros
Cons
What Recent Buyers Report
Recent buyers were able to install this BCG in a matter of minutes. Once installed, they tested it at the range with their AR-15 pistols. No failures or reliability issues were reported. The firing ability was smooth and had no other issues of concern.
Why it Stands Out to Us
This BCG is probably considered the best because it is simple to install and it will get your gun to work in the quickest time possible. Aside from that, the construction is solid and everything is assembled in place. It’s a drop-in BCG that’s ready to go when you are.
Who Will Use This Most
This is as close as you’re going to get to a universal BCG. Especially if you need one to install in your AR-15 pistol. Whether you’re building it from the ground up or simply upgrading it from something else, you want a BCG that is fully functional, smooth, and reliable each time you use your pistol.
What Could Be Improved and Why
Obviously, getting rid of the staked key would be a welcome improvement. In its place should be an integral key. It may not be much of an issue, but it will make the BCG a little more reliable than most.
Bottom Line
If you’re simply looking for the best of the best when it comes to BCGs, the Brownell Brand AR-15 9mm BCG could be something that you’re looking for. All you need to do is install this in your AR-15 9mm pistol and you’ll be ready to go no matter what you’re using your pistol for.
Runner-up:
Faxon Firearms - AR-15 9mm Bolt Carrier Group
Pros
Cons
What Recent Buyers Report
A lot of recent buyers were quite happy with the BCG’s overall function and durability. Another thing they noticed was that the overall reliability was top quality. No jamming, no firing issues, just exactly how a BCG should work according to most users. Installation was easy and free of any frustrations.
Why it Stands Out to Us
This is lightweight, easy to install and remove, and battle-tested to take on whatever application you put your AR-15 9mm pistol through. We always fancy ourselves as fans of something that won’t hit the shelves unless it passes all kinds of tests with flying colors.
Who Will Use This Most
This will be used by most AR-15 pistols users that are casual or competitive target shooters. This is designed to handle all kinds of constant gunfire. Most of the users will be shooters who will look for something that will give them the same reliability after 100+ rounds fired.
What Could Be Improved and Why
Despite no obvious cons, one thing that we should make you aware of is despite the fact that it’s heat-treated, it might stay warm for a while after extended use. Nothing to sneeze at, but the heat dissipation might be quite slow.
Bottom Line
If you’re looking for something solid and might be a direct threat to the Brownell’s “best overall” spot, the Faxon Firearms BCG might be your alternative choice if you’re looking for something that is strong, reliable, and works with almost any AR-15 9mm in existence.
3. J P Enterprises - AR-15/M16 9mm Bolt Carrier Group
Pros
Cons
What Recent Buyers Report
Most recent buyers were looking for a reliable BCG for their AR-15 pistols. Especially something that will last them for a long time. They were mostly casual target shooters or competitive shooters.
Both enjoyed the overall functionality and ability of this BCG and considered it a much better upgrade compared to their previous one. Some buyers were also building their pistols from the ground up and needed a functional BCG that was right out of the box.
Why it Stands Out to Us
This BCG is something that might have been created for the competitive shooter in mind. This was designed to handle pretty much all kinds of multiple firing episodes. For something that won’t jam even after 1000 shots, that’s quite a good sign. So it sticks out for its potential to be a long-lasting BCG, especially for the avid target shooter.
Who Will Use This Most
At risk of being repetitive, this is a target shooter’s BCG. So it will be most likely used by range shooters and competitive shooters alike. That’s because it’s strong enough to handle the impact of multiple gunshots. So it can take multiple hammer hits on a good day.
What Could Be Improved and Why
This may be modified a bit to ensure that it will work with all kinds of upper receivers. At this point, it’s compatible with most of them but not all of them. Thus some have resorted to making some modifications themselves (which might be kind of risky and could ruin the BCG if you’re not careful).
Bottom Line
The JP Enterprises AR-15/M-16 BCG might just be your best BCG that you can own if you’re planning on firing off a ton of rounds with your AR-15 pistol. A few BCGs have the potential to handle the multiple amounts of firing power. This one, in particular, might be one of them.
4. Foxtrot Mike Products - FM-9 Bolt Carrier Assembly
Pros
Cons
What Recent Buyers Report
Recent buyers were able to call this a high quality and very affordable BCG. One even went so far as to say that he got a lot more than what he paid for. Aside from the easy installation and quality construction, most users were able to fire off hundreds of rounds without a single reliability issue.
Why it Stands Out to Us
This is a BCG that is more than a budget BCG. It’s made from some high-quality steel that will definitely work to your advantage if you’re looking for something that is guaranteed to last you years or even decades. A long-lasting BCG in our opinion is more than good enough for us to choose this for our list.
Who Will Use This Most
This will be used by budget AR-15 9mm owners who want to get the best out of their pistols. So they want a BCG that is built to last them years. This way, it saves them money rather than have to go out and buy a brand new BCG in a few years time. They want something that can last them pretty much close to a lifetime. This BCG has that potential.
What Could Be Improved and Why
One of the things that might improve is making some adjustments to the size. That way, it won’t cause any issues with any AR-15 pistol lower receivers. Alternatively, it could be the pistol design itself. In that case, maybe a different BCG could be the solution.
Bottom Line
If you’re looking for a BCG that is reliable, tough all over and is affordable for most budgets then the Foxtrot Mike might be exactly what you’re looking for. Why spend more money all the time on ineffective BCGs when you can buy one and stick with it for many years? We know that a BCG like Foxtrot Mike’s won’t steer you wrong in the slightest.
5. Colt - AR-15/M16 9mm Bolt Carrier Group
Pros
Cons
What Recent Buyers Report
Most recent buyers were satisfied with it overall. It fits most Colt AR-15 9mm pistols without any issues. Plus, the installation was easy and required no modification. So it has the ability to work with a good amount of upper and lower receivers. After 100 rounds, it remained reliable for most shooters.
Why it Stands Out to Us
The Colt brand has long been appreciated by many pistol enthusiasts. And it’s also made its way into the hearts and minds of AR-15 enthusiasts everywhere. So why not make a BCG that brings a very powerful semi-automatic together with one of the most venerable brands of pistols? This BCG was made for the Colt enthusiast and that’s why we like it.
Who Will Use This Most
This will be used mostly for target practice applications. Competitive shooting and even home defense applications are also suitable. This is made for shooters who want their Colt AR-15 pistol to last them as long as possible (so long as they take great care of it).
What Could Be Improved and Why
This BCG has the ability to work with all kinds of charging handles. However, some charging handles may not be compatible with this BCG in particular. This might be something to be made aware of. Nothing a little testing and tweaking can’t fix.
Bottom Line
If you’re looking for a BCG that will be the perfect match for your Colt AR-15 9mm pistol, look no further than the Colt brand BCG. You won’t be disappointed once you install this puppy on your pistol and give it a spin. This is as close as you’re going to get when it comes to the best in reliability for a Colt-style pistol.
What is a Bolt Carrier Group?
Strictly speaking, the bolt carrier group is considered the heart of your 9mm. In fact, it’s the heart of any firearm. Think of it as an engine for your car. Without the engine, you cannot drive the car.
Without a BCG, you cannot fire your 9mm. Simple as that. A BCG is comprised of some key components that will work in conjunction with your 9mm’s firing ability. We will go a little deeper into what comprises a BCG in the next section.
Photo credit: gfycat.com
What Are The Components of a Bolt Carrier Group?
There are nearly a dozen components that comprise a bolt carrier group. Most of these are your pins and springs that will hold it all together. Of course, we cannot forget some of the major components as well. A BCG will house some of the following key components: the bolt itself, ejector, bolt carrier, extractor, and the firing pin.
Conclusion
The best 9mm BCG is out there, and one of the five listed above might fit your AR-15 9mm pistol the best. Be sure to double check which one stands out as your ideal BCG so you can make a choice without thinking twice.
Remember, this BCG is going to stick with you for the long term. So find one that is solid in construction and reliable in use so it can last you a long time rather than not at all.
