best ar9 uppers - cover

The Best 9mm AR Uppers in 2021

Kenzie Fitzpatrick


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There are plenty of benefits to converting your AR with a 9mm upper. The flexibility of PCCs has driven their popularity over the past 20 years, making them the go-to choice for those who want a multi-role pistol caliber rifle, and one of the main reasons I have one in my collection.

With all the options and benefits of building a pistol caliber carbine (PCC), it’s high time you get started.

In This Article:

AR9 Upper Comparison

Below is my list of the best AR9 uppers for 2021. I list the best choices in terms of value, performance, design, and cost.

Click on the name to head to the product page, read reviews and check prices or skip ahead to the list of upper receivers.

AR9 Upper Reviews

1. Palmetto State Armory

Palmetto State Armory (PSA) has recently hit the pistol caliber carbine market hard. Their products are always of high quality with a more modest price point.

The PSA PA-9 upper includes a Gen 4 hybrid 9mm bolt carrier group and charging handle, making this a competitive setup in one purchase. 

The barrel length is 10.5 inches, typical of a 9mm PCC but still considerably shorter than those used to a traditional 5.56/.223 rifle, which will generally see barrels in the neighborhood of 16 inches (or more). I find the 10.5-inch length to be a good middle-ground for mobility and accuracy.

The PSA flash can is designed to direct gasses and noises forward away from the shooter because of the shorter length of this upper. This is great for keeping the shooter safe from hot gasses and helping minimize barrel rise. 

The last thing to note is the handguard is M-Lok, so be sure any attachments added to the handguard are compatible before purchasing. I tend to run M-Lok with both PCC and AR builds, which prevents me from shelling out for accessories twice.

2. Foxtrot Mike

Foxtrot has a variety of 9mm AR-15 uppers, but the most similar to a rifle setup is the 16-inch upper receiver. Converting your AR-15 to a 9mm AR with this length barrel will help you improve your accuracy and allows you to shoot cheaper 9mm ammo rather than 5.56 or .223.

This upper is complete with a non-reciprocating forward charging handle, a bolt carrier group with a hard melonite finish, and an M-Lok handguard.

This receiver is compatible with any lower that uses Glock magazines, so you can kill two birds with one stone if you tend to run Glock handguns, which a number of my range buddies tend to look for.

3. Angstadt Arms

The 6-inch barrel complete 9mm upper is an excellent option if you’re building a home defense or truck gun. This upper is also suppressor-ready, which is a logical addition to this if it is a defensive firearm. The handguard is 5.5 inches long and ultralight. This upper is compatible with any 9mm AR-15 dedicated lower receiver.

This upper includes a 9mm BCG and the high-quality Radian Weapons Raptor ambidextrous charging handle.

4. Stern Defense

Stern Defense makes a great mid-length 8.5-inch barrel option, a solid choice for a fun PCC build. This upper is unique as the free float M-Lok handguard extends beyond the barrel’s end.

The muzzle includes a blast can to extend beyond the handguard. The Stern Defense 9mm bolt is compatible with Colt SMG and Glock magazines.

5. Faxon Firearms

If you’re all about running 9mm carbines in competitive shooting, this complete upper is a great option to match what you’re used to on an AR-15 platform. The 16-inch taper 9mm barrel is accurate for shooting at distance. This upper is compatible with lowers that use both Colt or a Glock mag.

The Gen 2 9mm bolt-carrier group, charging handle, and A-2 style flash hider are all included for a complete drop-in-ready setup.


CMMG is known for high-quality AR- 15 rifles and has broken into the 9mm AR-15 uppers market. This specific model features an 8.5-inch barrel with an M-Lok handguard. The barrel comes with the SV brake muzzle device already installed. This upper is compatible with Glock magazines only and comes with a charging handle and a BCG.

What is an upper anyway?

9mm AR9 Uppers - Unfinished Uppers
Two main components make up a rifle or pistol caliber carbine, an upper and a lower.

Two main components make up a rifle or pistol caliber carbine, an upper and a lower.

The lower is the only serialized piece that requires an FFL transfer. An upper or upper receiver is the part that contains the bolt carrier group and charging handle, and given they’re compatible with lowers you get the same “lego for adults” quality of traditional ARs in the smaller 9mm format.  

The upper is also where the barrel and handguard attach. The most important bit here is the upper and lower need to be compatible and fit together snugly for your firearm to be accurate and safe to fire.

Why a PCC upper?

9mm AR Uppers - Upper and Lower Disassembled
The flexibility of PCCs has driven their popularity over the past 20 years, making them the go-to choice for those who want a multi-role pistol caliber rifle.

PCC’s came about to fill several needs; 9mm carbines are in the ballpark of AR-15 pistols or short-barreled rifles in terms of interoperable uppers and lowers, but with less hassle around brace rules or federal tax stamps. You get a lot of he benefits with less runaround — something I’m always willing to invest in. 

BCG & Charging Handle
PCC uppers are configured for 9mm ammunition from the BCG to the ejection port and everything in between.

9mm being one of the most popular rounds on planet earth, complete AR9 uppers are chambered in Herr Luger’s cartridge and engineered to integrate with the AR platform. A PCC upper must shoot 9mm ammunition as everything from the ejection port size to the BCG changes to support that specific cartridge. Plus, I tend to find 9mm ammo is considerably cheaper than full-on 5.56 NATO, so you can save a few bucks by transitioning to a PCC for regular shoot days. 

Less recoil but full rifle length

Different 9mm ammo cases brass aluminum nickel
Beyond the ease of use, 9mm round scome in a massive array of options.

PCC’s throw off a lot less recoil than 5.56 and .223 rounds, making them an ideal choice for women or children who want to get familiar with shooting a rifle-length gun without rifle-level recoil.

Mil-spec PCC uppers with a 16-inch barrel can provide the same rifle fundamentals practice with the bonus of saving money using the relatively cheap 9mm ammo.

Lastly, PCC uppers with shorter barrels between 6 and 8.5 inches make excellent self-defense firearms or truck guns. Most of these suppressed can be as soft as shooting a .22lr.

9mm Upper Compatibility

9mm AR Uppers - Upper and Lower Together
The easiest way to build a PCC with with a dedicated 9mm lower & upper. There are mag well adapters for standard AR lowers that make it possible as well.

There are two ways to install a 9mm upper and create a pistol caliber carbine. The easier option is connecting a 9mm upper onto a dedicated 9mm lower. These are easy to install because the lowers are designed to PCC specs, and the mag well is already set up to accept Glock or Colt magazines.

The second way is to attach the 9mm upper onto a standard AR-15 lower with a mag well adapter. AR uppers match AR lowers’ specifications, so the fit with an AR lower and PCC upper may leave a little to be desired.

9mm AR Uppers - Mag Well
A 9mm mag well is a smaller target that a traditional AR mag well, and will require more precision to hit consistently with quick mag swaps.

Choosing the Best AR9/9mm Upper for You

The first question you have to ask yourself is what purpose this gun is serving? Barrel length is the most significant factor when determining your 9mm carbine’s purpose. A shorter barrel will be suitable for defensive situations, and a longer barrel can be used in competition or to replicate the size and weight of a traditional AR-15.

Lighter & easier to control

Weight is another factor to take into account. If you struggle to control a fully loaded 16-inch PCC, consider a 10.5-inch. This modularity gives you a great opportunity to get the fit just right, which is a huge benefit for people like myself, who often struggle with one-size-fits-all kinds of products.

Also  – any gun is only as good as its sights. It’s rare to find anyone using iron sights on these guns, but those unicorns do exist! Most red dots, for example, will be compatible with Picatinny rails, so ensure your handguard is configured accordingly. 

All the same rail compatibility 

9mm AR Uppers - Different Handguards
M-Lok & KeyMod PCC uppers. PCC uppers will give you the same rail and mounting options of rifle-caliber uppers, with possibly less overall room given the tend toward shorter barrel length.

Similarly, the uppers mentioned above all come with an M-Lok compatible handguard or Lok rail. If mounting a flashlight or laser on the handguard, mount it to the side — and out of the way — of the sights. Mounting systems like M-Lok are so crucial for this reason alone — they keep your sight line clear.

Magazine choice matters

Magazine choice is an essential factor in which compete upper you’ll run. Some only use Glock magazines, while others can also accept Colt mags. The magwell for a dedicated 9mm lower can take some getting used to if you’re coming from the traditional AR world — it’s a considerably smaller insertion target. 

Pro tip: if you’re running an AR-15 lower with a magwell conversion, use the inside of the magwell to ease the magazine in. It will take a lot of the guesswork out of reloads and helped me shave a lot of time off my shots.

Drop- in vs building your own

The last consideration is how competent you are in building a 9mm PCC vs. going with an easy drop-in installation. 

While we found the best AR9 complete uppers on the market that require little to no installation, stripped upper receivers allow you to start building a custom PCC from scratch.

Whatever you choose, make sure you know what you’re doing or take your parts to a reputable gunsmith.


Pistol caliber carbines were purposefully designed for self-defense, competitive shooting, and fun. Whatever your intentions, take your time, pick the upper that will best suit your needs, and most importantly — enjoy your new 9mm build!


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