Best AR-15 9mm Conversion Kits [2020]

Are you currently looking to convert your AR-15 into a 9mm variant? If so, to make this happen you will need to invest in a 9mm conversion kit.

Best Budget Pick: Stern Defense AR-15 9mm Conversion Adapter

Stern Defense AR-15 9mm Conversion Adapter

The Stern Defense AR-15 9mm Conversion Adapter is an excellent choice for a 9mm conversion kit so long as you are using Glock magazines (and it can work for .40 caliber as well). Built out of 4140 steel, this conversion adapter also comes with a bolt hold open feature on the last round and an easy-to-access magazine release. However, it also needs a Glock cut bolt to install.

See on Brownells

Best Value Pick: Rock River Arms AR-15 9mm Conversion Block

Rock River Arms AR-15 9mm Conversion Block

The Rock River Arms AR-15 9mm Conversion Block is designed to function with Colt and Uzi magazines. Built out of high quality steel and aluminum to mil-spec standards, it’s designed so you can still use the standard magazine catch on your AR-15.

Seen on Brownells

Best Overall Pick: Hahn Precision 9mm Dedicated Conversion Block

Hahn Precision 9mm Dedicated Conversion Block

The Han Precision 9mm Dedicated Conversion Block is available with both a top loading and bottom loading version. Designed for Uzi or Colt-style magazines, it’s very durable and comes with a last round hold open feature and the ability to reliably feed hollow point ammunition.

Seen on Brownells

One of the biggest benefits to the AR-15 is the fact that it is among the most modular firearms in existence. Even if your AR-15 is currently designed to fire centerfire rifle ammunition such as 5.56x45mm NATO, you can still convert it to fire pistol ammo such as the 9mm. You will just need to make a handful of modifications and investing in a new conversion kit is one of those modifications.

In this guide, we will cover the benefits of transforming your AR-15 into a 9mm, the top qualities to look for in a conversion kit, and then our top three choices for the best 9mm AR-15 conversion kits in 2020.

What Are The Primary Advantages of Having An AR-15 In 9mm?

There are many advantages, as well as disadvantages, to having an AR-15 in 9mm. Let’s get the disadvantages out of the way first.

The 9mm is a pistol round, and therefore has much less range and power than a rifle round such as the 5.56 or .223. This is a simple fact. Your 5.56 AR-15 will hit harder, and it will shoot farther. It’s a better choice for longer distance shooting and for hunting medium sized game such as deer, pronghorn, or wild boar.

But the 9mm version of the AR-15 enjoys some advantages as well. For one thing, if you have a pistol on you in 9mm Luger, you can have two weapons that fire the same caliber. This keeps things incredibly simple.

You can make things even simpler if you are able to use the same magazines. Some AR-15s in 9mm will accept Glock factory magazines for instance. If you are using a 9mm Glock as your main weapon, you can then use the same magazines for both firearms.

Also take note that pistol magazines are much smaller and lighter than rifle magazines, which means that they will have less of a burden on you as part of your load out. You will most likely be able to move faster as you are held down with less weight.

Another reason to go with a 9mm AR-15 is for reduced recoil. The 9mm round is smaller than the 5.56, and therefore has less of a kick. Faster follow up shots will be easier, and smaller statured people in your family or group should have an easier time shooting it as well.

Finally, the 9mm round creates less noise and muzzle flash than the 5.56. If you are planning on using your AR for home defense, these are massive benefits that can help to improve your effectiveness in the tight confines of your home. The reduced noise and muzzle flash mean that you likely won’t be as disoriented as if you were to shoot a 5.56 rifle in your home.

Add the fact that you can use both a carbine and a pistol with the same magazines and ammunition as your home defense setup, and you should start to see why there really is good reason to consider having an AR-15 in 9mm.

If you agree that having an AR-15 in 9mm would be a good idea, you have two options: either buy an AR-15 in 9mm (called an AR-9) or otherwise convert your existing AR-15 into a 9mm version.

How Can You Convert An AR-15 to 9mm Luger?

The big question you may have on your mind is this: how are you supposed to convert an AR-15 in 5.56 or .223 into a 9mm Luger model anyway?

Well, let’s put it this way: the AR-15 is without question the most modular rifle in existence. It’s often referred as the ‘Lego of the firearms world’ by those in the gun community for this very reason. In other words, it is extremely simply to make adjustments and modifications to the weapon.

The only other firearm platforms that come anywhere close in terms of modularity to the AR-15 are the Ruger 10/22, Glock pistol, and the 1911 pistol.

So, with this in mind, there are really no shortage of options for converting your AR-15 into a 9mm model. In doing so, you will in essence be converting your AR-15 into an AR9, as this is the name typically given to a 9mm caliber AR carbine.

You will need to replace your BCG with a new 9mm bolt carrier group, and a complete conversion upper receiver that fits into the lower receiver. This will enable you to use your existing 5.56 lower receiver with an upper designed for the 9mm. Alternatively you could get a 9mm AR lower.

Another way is to keep the existing upper receiver, but to replace it with a new barrel, bolt, and a magazine adapter that can fit 9mm sized magazines (such as the Colt or Uzi style magazines, or the Glock style magazines).

To build an upper receiver in the 9mm Luger is actually a cheaper process than you may imagine. You’ll simply need to replace the bolt carrier group and the buffer with 9mm models, and then insert a block into the magazine well (which you may need a barrel nut wrench for).

The reason to buy a conversion kit is that it will be a more affordable option than buying the individual pieces. Buying the separate pieces individually will add up in price very quickly, to the point that it could even supersede the price of simply purchasing a brand new AR9 carbine or pistol on its own.

Installing a 9mm barrel into your upper receiver is also easier than you may think, and actually does not require the aid of a gunsmith. The back of a 9mm barrel is the same size and diameter as a 5.56 barrel, and the barrel nut is the same a well. All you need to do is torque the barrel nut in with your hand guard of choice.

A chief difference between a 9mm barrel and a 5.56 barrel is that the muzzle threads are different on a 9mm, forcing you to invest in a flash hider, compensator, or any other muzzle device designed specifically for the 9mm and therefore to avoid any chance of a catastrophic failure.

You will then need to replace the 5.56 bolt with a 9mm bolt, but you should be able to keep the same buffer and charging handle of your 5.56 version.

At that point, the only thing left for you to do is to purchase a special adapter that can accept 9mm magazines and reliably feed 9mm ammunition from the magazine into the chamber. It is these conversion devices that we will be discussing later in this guide.

These adapter come in two primary forms: one that is inserted beneath the lower receiver and is then held in place with the magazine catch, and the other is inserted through the top of the lower receiver and is held by the lips of the receiver. Either one works fine.

Furthermore, changing back from a 9mm AR into a 5.56 AR is very easy, and you just need to reverse the above process. Get rid of the magazine adapter, and replace the barrel, buffer, and bolt carrier group back with the 5.56 models.

As noted previously, the AR-15 really is one of the most modifiable guns in existence. You can have the entire conversion done in only a matter of minutes.

Next, let’s take a look at the qualities to look for in a 9mm conversion kit.

Buyer’s Guide For The Best AR-15 9mm Conversion Kits

These are the most important factors to consider when looking for a new conversion kit for your AR-15:

Magazine Compatibility

First and foremost, you need to make sure that your conversion kit is designed to fire the 9mm magazines that you want or need it to. Not all conversion kits will work with all 9mm AR magazines, and on the contrary, most are designed specifically for different kinds of magazines.

The most common magazine types for a 9mm AR-15 are Glock magazines, Colt-style magazines, and Uzi magazines. Most of the time, a conversion kit is able to handle both Colt and Uzi magazines, but not Glock magazines. If you haven’t thought about the types of magazines that you want to use in your conversion gun, it will be a good idea to do so before you buy.

If you need any help making this decision, just remember that Glock-style magazines in 9mm like you would use for the Glock 17 or the Glock 34 are generally cheaper and more available (at least they were before the current ammo and magazine shortage, which has undoubtedly caused a lot of problems in the industry.

Durability

The best 9mm AR-15 conversion kits are made out of high quality steel and/or aircraft grade aluminum, and then often further coated in a rust and corrosion resistant finish such as nitride. Remember that your conversion kit is essentially going to become a part of the gun itself, and therefore needs to be built to the same standards as your actual AR-15.

Ease of Installation

Assuming that you want the conversion process to be as stress free as possible, you should make sure that you conversion kit has a drop-in design, which means that it can be installed into the AR-15 without any specialized tools or the need of a gunsmith.

Alternatively, even if the conversion kit does require extra tools to install it should still be easy and straightforward to install. You shouldn’t have to go to a gunsmith to install your conversion kit.

Last Round Hold Open Feature

Will the conversion kit ensure that the bolt to the AR-15 will hold open on the last round that you fire through it? This honestly doesn’t impact the reliability of your weapon either way, but it certainly is a nice feature to have.

Reliability

Last but certainly not least, does your conversion kit enable the reliable feeding of ammunition from the magazine into your AR-15? If the follower angle of your conversion kit is too steep, it can cause feeding issues to occur, and particularly with the last four to five rounds in the magazine.

The 3 Best 9mm AR-15 Conversion Kits For 2020

Now that we’ve covered how to upgrade your AR-15 to 9mm, here are our choices for the top three best 9mm AR-15 Conversion Kits for 2020:

Stern Defense AR-15 9mm Conversion Adapter

Stern Defense AR-15 9mm Conversion Adapter

The Stern Defense 9mm Conversion Adapter is an excellent choice for an AR-15 9mm adapter. It was originally made out of high quality aircraft grade 6061 aluminum, but lately Stern Defense has been making it using even more durable 4140 alloy steel.

This conversion adapter is designed to be used with Glock-style 9mm double stack magazines. It can work with Glock factory magazines, but as for aftermarket Glock magazines you will need to check compatibility yourself. And for what it’s worth, this adapter can also fit .40 caliber double stack Glock magazines in the off chance that you want to convert your AR-15 to the .40 S&W caliber instead.

Stern Defense AR-15 9mm Conversion Adapter close-up

This conversion adapter also comes with a last round hold open feature, which means that the bolt to your AR-15 will lock back when you fire the last round out of the magazine. It also has a built-in magazine release to make it easy to eject the spent magazines.

Take note that this conversion adapter also requires the use of a Glock cut bolt, and you may need to shave a little off the top of the ejector to get it to install depending on the bolt you are using.

Stern Defense AR-15 9mm Conversion Adapter on AR

Overall
All in all, the Stern Defense AR-15 9mm Conversion Adapter is a solid choice for a 9mm AR-15 adapter if you are planning on using Glock magazines. It’s built out of a very durable 4140 steel materials and has a magazine release that’s easy to access, along with a last round bolt hold open feature. However, it does require Glock cut bolt to install, and you may need to shave a little off of the ejector from your AR-15 to get it to work.

See on Brownells

Pros
  • Works with both Glock style 9mm and .40 caliber magazines
  • Built out of durable 4140 steel alloy
  • Has a built in magazine release
  • Has a last round bolt hold open feature
Cons
  • Does not work for pistol magazines other than Glock
  • Requires the use of a Glock cut bolt

Hahn Precision 9mm Dedicated Conversion Block

Hahn Precision 9mm Dedicated Conversion Block

The Hahn Precision 9mm Dedicated Conversion Block is available in two versions: a top loading and a bottom loading version. The bottom loading version inserts into the bottom of the receiver and is secured using a tension feature to prevent it from accidentally coming off. The top loading version drops in from the top of the lower receiver and will require you to remove the bolt release in order to install it.

The Hahn Precision is very durable, and has a last round hold open feature so the bolt will lock to the rear when you fire the last round from the magazine. This conversion block is also designed for the reliable feeding of all 9mm ammunition, including self-defense hollow point loads. It’s designed to function well with Colt and Uzi magazines, but not Glock magazines.

Overall
Overall, the Hahn Precision is a solid choice for a 9mm AR-15 conversion kit so long as you are using Colt or Uzi magazines. Available in either a top loading or bottom loading edition, it comes with a last round hold open feature and can function well with hollow point ammunition.

Seen on Brownells

Pros
  • Available in a top loading or drop loading version
  • Compatible with Colt and Uzi magazines
  • Has a built-in hold open feature on the last round fired
  • Cut for reliable feeding with hollow point rounds
Cons
  • Not compatible with Glock magazines

Rock River Arms AR-15 9mm Conversion Block

Rock River Arms AR-15 9mm Conversion Block

The Rock River Arms AR-15 9mm Conversion Block is designed to function with Colt and Uzi style magazines. It will lock to the rear with the Colt magazines, but not when using the Uzi magazines. It will not work with Glock-style magazines.

Rock River Arms AR-15 9mm Conversion Block back

Built out of durable steel and aluminum and built to mil-spec standards, the Rock River Arms is a bottom loading design that uses a set screw to get the magazine block secured to your AR-15. This enables you to use the standard magazine catch on your AR-15 rather than having to install a new one.

Rock River Arms AR-15 9mm Conversion Block side

Overall
Overall, the Rock River Arms is a good choice if you want a durable and high quality mil-spec grade 9mm conversion kit. It’s designed in such a way so you can use the standard magazine catch on your AR-15, and it’s fully compatible with Colt and Uzi magazines.

Seen on Brownells

Pros
  • Built out of durable steel and aircraft grade aluminum
  • Built to mil-spec standards
  • Designed to function with Colt and Uzi magazines
  • Allows you to use the standard magazine catch on your AR-15
Cons
  • Does not work with Glock magazines
  • Does not lock open on Uzi magazines (but it will with Colt magazines)

Wrap Up

And that concludes our list of the top three best 9mm AR-15 conversion kits for 2020!

Any one of the three conversion kits that we have covered here today will be a solid option for helping to convert your AR-15 from its current rifle caliber configuration into a 9mm version. Alternatively, you can follow the buyer’s guide that we set to ensure that you find a high quality model as well.

Sniper Country Team
Written by Sniper Country Team

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