If you are currently looking for the best 9mm bolt carrier groups for your AR9 carbine, you’ve come to the right place.
Best Budget Pick: Brownells 9mm Bolt Carrier Group
Despite being a little bit heavy and coming with a useless staked key, the Brownells 9mm Bolt Carrier Group is a solid pick for a BCG thanks to its affordable price, ease of installation, and the fact that it was built to be compatible with as many other AR9 parts as possible.
Best Value Pick: Faxon Firearms 9mm Bolt Carrier Group
The Faxon Firearms 9mm Bolt Carrier Group is a very lightweight BCG that will not add very much weight to your AR9, which makes it an excellent choice for AR pistols in particular. It’s also heat treated to help improve its heat resistance and long term durability.
Best Overall Pick: JP Enterprises AR-15 9mm Bolt Carrier Group
The JP Enterprises AR-15 9mm Bolt Carrier Group is one of the most durable and reliable bolt carrier groups for a 9mm AR market, designed to last for literally tens of thousands of rounds without having any issues. It’s also fully compatible with most 9mm AR parts as well, and as a drop-in BCG installation should be an absolute breeze.
If you are building an AR9 from the ground up, a bolt carrier group (which is a part of the upper receiver) is simply one of the most important components you need to get. That’s because without a bolt carrier group, your AR9 will be completely incapable of firing in the first place!
When you purchase a complete upper receiver for your 9mm AR, it will already come with a bolt carrier group installed in it. However, if you purchase a stripped upper receiver, it will most likely not come with a bolt carrier group (or BCG) installed in it, and you’ll need to buy it separately and install it yourself. Additionally, even if your upper does come with a BCG, you may want to purchase a better one for an upgrade. Speaking of upgrades, here is our guide on 9mm AR lowers.
In this piece, we’ll dive into why you should consider the 9mm round for an AR carbine to begin with, what the bolt carrier group is to begin with and how it works, the top qualities to look for in a 9mm bolt carrier group, and then our picks for the top three best 9mm bolt carrier groups for 2020.
By the way, did you know there are AR-15 9mm conversion kits that let you convert your 5.56 lower to accept 9mm magazines? Definitely worth looking into if that’s an option for you.
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Why Go With The 9mm Round For An AR?
Why would you want to go with a 9mm Luger for an AR to begin with? After all, the vast majority of AR rifles and carbines are chambered for rifle rounds such as the 5.56x45mm NATO rounds, which offer much greater range and superior ballistics than pistol rounds such as the 9mm.
While it is true that the 9mm rounds lacks a lot of the power, range, and energy of a rifle round such as the 5.56, there are still a handful of reasons to consider getting a 9mm AR. Just so you know, the terms 9mm AR-15 and AR9 are interchangeable, as the AR9 is literally just an AR-15 carbine or pistol that is chambered for the 9mm round.
The first reason to get an AR9 is for ammo commonality. Many service pistols such as the Glock 19, Beretta 92FS, Smith & Wesson M&P, Walther PPQ and so on are chambered for the 9mm Luger round, which is the most common pistol round in the entire world.
By having one round for both your carbine and your pistol, well, you can interchange the ammunition between both weapons. In some cases, you can even interchange the magazines. For example, some AR9 pistols will accept Glock 9mm magazines. If you have a Glock 34, Glock 17, or a Glock 19 for your handgun, you can use the same magazines for both weapons. This can make for a neat and convenient set up for home defense or for a tactical situation.
Another reason to go with the 9mm round for an AR is it kicks less than the 5.56. While the 5.56 is already easy to shoot, the 9mm out of an AR is even more so. Faster follow up shots will be easier, and people of an overall smaller stature should have an easy time shooting it as well.
In addition, the 9mm round will have less noise out of an AR than the 5.56 as well. In the confines of your home in a home defense situation, this will be very desirable, as the loud noise of a full powered rifle round can be very disorienting (even when you are pumped full of adrenaline).
Last but not least, many 9mm AR9s are incredibly compact, particularly when you go with an AR9 pistol. They are very easy to maneuver in tight conditions, which will make them valuable weapons both for home defense or as a vehicle gun.
In summary, there are many reasons to go with a 9mm AR carbine or pistol. Even though it will lack the range and power of a 5.56 AR (or another rifle round) it still serves a valuable purpose and can be a great addition to your arsenal.
If you are looking to build your own personal AR9, all of the parts you need to buy to complete the weapon are important and you should research them all carefully. But the one component that perhaps deserves more attention than all of the others is the bolt carrier group, because this is the heart of your AR9 that allows the firearm to even shoot in the first place.
What Is The Bolt Carrier Group?
What is the bolt carrier group and what function does it serve exactly? Well, to put it bluntly the bolt carrier group is the beating heart of an AR-15 rifle. Let’s put it this way: without a bolt carrier group, your AR9 will be incapable of firing.
The bolt carrier group is also a part of the upper receiver to an AR-15. When you install it, you’ll slide it into place through the rear of the receiver until it locks into place.
How the bolt carrier group works is when you fire a round, the gas will be redirected from the spent cartridge and travel back down into the bolt carrier. The gas will fill up the chamber that has been created by the gas rings of the bolt, and this action forces the bolt carrier back against your AR’s recoil spring.
As the bolt carrier travels backward, the bolt will twist in order to unlock it from the chamber. This permits the entire action of the rifle to cycle to the rear. The spent shell casing will be ejected from the chamber, and a new round from the magazine will be loaded into the chamber to permit the rifle to be fired again.
Without the bolt carrier group, the firing pin would not be able to strike the primer on the loaded round to fire the weapon in the first place, the spent shell casing could not be grabbed and ejected out of the weapon, the hammer of the AR could not be cocked in order to fire it again, and a new round could not be loaded from the magazine to chamber the weapon again.
The individual components of the bolt carrier group are as follows:
Also known as the bolt carrier housing or just the housing, the bolt carrier simply contains all of the following pieces to forge the bolt carrier group as a whole. The bolt carrier also works to contact the buffer and spring and is what absorbs the force of the round being fired and ejected and a new round loaded. The best bolt carriers are built out of 158, 8620, or 9310 carpenter steel for good durability.
Also known as the gas key, the carrier key is a protrusion located on the top of the bolt carrier designed to absorb the gas that comes from the gas tube. The carrier key is hollowed so the gas can pass through it and then travel into the rest of the bolt carrier. It is the carrier key that then permits the bolt and the extractor to rotate, and thus lock or unlock from the firing chamber.
Bolt Gas Rings
The bolt gas rings are designed to trap the gas as it expands, which allows the bolt to operate. If the bolt gas rings did not exist, the gas would just be dispersed into the upper receiver, and the entire point of the bolt carrier group to begin with would be pointless.
Bolt and Extractor
The bolt and extractor work together as a single unit, even though they serve two completely different functions. The bolt is shaped like a star in the front, which allows the bolt carrier group as a whole to lock or unlock inside the chamber. It will rotate fifteen degrees to lock or unlock the chamber.
Meanwhile, the extractor is designed to hook onto the rim of each individual 9mm round to hold it in place and load it into the chamber. When the gun cycles, a spring located on the ejector forces the casing to exist the receiver through the ejection port.
The firing pin is what strikes the primer of the 9mm bullet when you pull the trigger, and thus allows the firearm to fire. The pin barely sticks out of the head of the bolt, and you will visibly notice it next out the ejector.
Finally, the cam pin prevents the bolt from rotating too far when it unlocks. The cam pin is placed through the carrier, via a hole located next to the bolt. A cut out located on top o the carrier allows the cam pin to rid back and forth. There is also a hole located in the middle of the camp pin that permits the firing pin to slide through. It also ensures that the cam pin is oriented correctly, so it will not fall out and cause issues.
Buyer’s Guide For A 9mm Bolt Carrier Group
These are the most important factors to consider when looking for a new bolt carrier group for your 9mm AR9:
First, you should make sure that your bolt carrier group comes MPI, or magnetic particle inspected. Bolt carrier groups, as we’ve discussed, are literally the beating heart of your 9mm AR carbine. As a result, they are subjected to lots of pressure as you fire rounds on the range (specifically, a bolt carrier group will be subjected to literally tens of thousands of pounds per square inch).
If any part of your BCG at all suffers a crack or a fissure, then the entire firearm could have a catastrophic failure (meaning it could literally blow up in your arms and cause a severe injury). To prevent this, bolt carrier groups undergo what is called magnetic particle inspection.
Specifically, the BCG will be placed into a magnetic field that is caused by two electromagnets. A liquid solution of magnetic particles will then be placed over the steel, which will identify to cracks and fissures located on or beneath the surface.
Avoid any 9mm BCG that does not come certified with an MPI.
In addition to magnetic particle inspection, your bolt carrier group should also come with high pressure testing, or HPT. This is where a high pressure cartridge is fired through an AR9, meaning that the cartridges rates much higher than SAAMI rated specifications for the 9mm round.
If the BCG holds up well without any noticeable wear from the high pressure cartridge, it practically guarantees that it can handle repeat fire from rounds at or below the SAAMI specifications.
Avoid buying a 9mm BCG that does not come certified with HPT.
The best bolt carrier groups are drop-in bolt carrier groups, which simply means that they can be easily installed into an AR9 without you needing to employ the services of a gunsmith. Ideally, your bolt carrier group can be installed into your upper receiver without the use of tools either.
Last but not least, cost matters. When you’re assembling your AR9 especially, all of the parts are going to add up in cost, and they can add up quickly. As a golden rule, bolt carrier groups typically cost anywhere from one hundred to three hundred dollars depending on the group. You shouldn’t need to pay anymore beyond this general price range.
The 3 Best 9mm Bolt Carrier Groups For 2020
Now that we’ve covered why you need to upgrade your 9mm bolt carrier group and what to look for in one, here are our top three choices for the best 9mm bolt carrier groups for 2020:
Brownells 9mm Bolt Carrier Group
The Brownells 9mm bolt carrier group is incredibly easy to install and does not require the services or aid of a gunsmith because it’s a drop-in BCG. It offers a solid construction at a relatively affordable price.
Brownells also designed this bolt carrier group to be compatible with as many AR9 parts and upper receivers as possible. This should give you peace of mind knowing that this BCG is likely to work with most other AR9 components that you purchase as you assemble your carbine.
That being said, the staked key that comes installed on this upper receiver is not truly necessary (the BCG could function just fine without it) and it’s also a bit heavy for a BCG as well, so it will add a little bit of extra weight to your AR9.
But as a whole, you’re getting a solid BCG with the Brownells that should last you a lifetime and without breaking your bank. The fact that it’s designed to be highly compatible with most other AR9 parts is also a welcome feature.
All in all, the Brownells 9mm Bolt Carrier Group is a solid option for a BCG. It’s durable and easy to install, even if it also is a little heavy.
- Very high quality finish
- Very positive extractor to ensure good ejection
- Very durable
- Incredibly easy to install
- Nitride finish is excellent for rust and corrosion resistance
- The staked key it comes with is not really necessary
- Heavy for a 9mm bolt carrier group, so it will add extra weight to your AR9
Faxon Firearms 9mm Bolt Carrier Group
The Faxon Firearms 9mm Bolt Carrier Group is a very lightweight bolt carrier group that is also very easy to install or take out of your AR9 pistol or carbine. It’s also heat treated to ensure that it will hold up well under extended use.
This is a good example of a bolt carrier group that will be a good choice for casual shooters who just want something that will work. Since it’s very lightweight, it will not add very much weight to your AR9 either, which will make it a solid choice for an AR pistol where both compactness and lightness will be highly desired features.
Overall, the Faxon Firearms is a solid choice for a 9mm BCG. It’s very lightweight, easy to install, and comes heat treated for superior durability and longevity over many other 9mm AR BCGs floating around on the marketplace.
- Very easy to install
- Lightweight and will not add very much weight to your AR9
- Heat treated to hold up well after extended use
JP Enterprises AR-15 9mm Bolt Carrier Group
The JP Enterprises AR-15 9mm Bolt Carrier Group may be expensive, but it’s also specifically designed by JP Enterprises to be as durable as possible and to last for tens of thousands of 9mm rounds without any issues. If you’re looking for a bolt carrier group that you know will last for multiple lifetimes, meaning that you can pass it on down to future generations, this is the BCG to go with.
JP Enterprises also designed this bolt carrier group to be compatible with as many 9mm AR parts as possible. As a drop-in bolt carrier group, it’s also incredibly easy to install into your 9mm AR.
Overall, if you want a 9mm bolt carrier group of the utmost durability and reliability and are willing to pay a premium price for it, then the JP Enterprises bolt carrier group deserves your close attention.
- Excellent choice for prolonged shooting sessions
- Compatible with most AR9 carbines and rifles
- Incredibly durable
- Very easy to install
- Very expensive
And that concludes our list of the top three best 9mm bolt carrier groups for 2020!
Any one of the three bolt carrier groups for a 9mm AR that we have covered here today will be a solid option, and furthermore, you can also choose any other bolt carrier groups floating around on the market that follow the buyer’s guide section we listed out above as well.
Remember that the bolt carrier group is the beating heart of your 9mm AR carbine. It directly impacts the shooting performance of your carbine, and without it, you couldn’t even shoot your carbine to begin with!