Are you looking to upgrade your existing 9mm AR (AR9) or build a new AR9 from the ground up? Either way, you’ll need to invest in a good lower receiver. We’ll walk you through the best 9MM AR lowers and give you the skinny on what is best for the situation.
The lower receiver of an AR9 is what houses all of the lower components, including the trigger group, handguard, magazine, and stock. Since it’s literally one of the most important parts to have for your AR-style rifle or carbine, it’s very important to know what to look for in a lower receiver and what some of your best options are.
This guide covers the top qualities to look for in a 9mm AR lower and my picks for the top three best AR9 lowers available today.
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Qualities To Look For In A 9mm AR Lower Receivers
Here are the top qualities to look for in a 9mm AR lower:
Durability
The first feature to look at in a lower receiver is durability. One of the best kinds of materials to look for is forged aircraft-grade 7075 aluminum. Not only is aluminum very durable, but it’s also very lightweight. Many metal-framed pistols, such as the Beretta 92FS, make use of aluminum frames for the same reasons.
Rust Resistant Finish
Durability is very important in a lower receiver to ensure longevity, but equally important is ensuring you have rust and corrosion-resistant finish coated over that receive. If your lower is ever exposed to rain, snow, or humidity, a rust-resistant finish is absolutely crucial.
One of the best choices for a rust-resistant finish is a hard coat anodized finish. Additional options include parkerizing, stainless steel, or nickel boron, or even coatings like Cerakote or Duracoat.
9mm Magazine Compatibility
AR9s can be separated into two primary camps: those that accept Glock-style 9mm magazines, and those that accept Colt SMG 9mm style magazines. When choosing a lower receiver, think ahead in regards to what kind of magazines you’ll be using.
Both Colt and Glock style magazines work, but the Glock magazines are definitely cheaper, more available, and have more aftermarket options. That being said, not all AR9 lower receives will accept all aftermarket Glock magazines either, so keep this in mind.
The 3 Best 9mm AR Lowers
Here are my recommendations to the three best 9mm AR lowers on the market today:
| Product Name | Where to Buy | |
|---|---|---|
 | CMMG AR-15 Dedicated Lower Receiver |  |
 | FoxTrot Mike Products AR-15 FM-9 Billet Stripped Lower Receiver | |
 | Palmetto State Armory PX9 Lower Receiver | |
1. CMMG AR-15 Dedicated Lower Receiver
The CMMG AR-15 Dedicated Lower Receiver is a stripped lower receiver that comes equipped with an ejector, bolt catch, and feed ramp that have been optimized specifically for the 9mm round. Built out of aircraft-grade aluminum and coated in a Teflon anodized finish. The Teflon not only makes the lower very resistant to rust and corrosion, but it also helps to smooth the operation of the individual components.
The CMMG does not accept 9mm Glock magazines, but it does accept 9mm Colt SMG magazines or Uzi magazines that have been specially modified.
Features:
- Built out of aircraft-grade aluminum
- Coated with a Teflon hard coat anodized finish
- Includes bolt catch, feed ramp, and the ejector
Pros:
- Built out of lightweight and durable materials
- Accepts Colt 9mm SMG or Uzi 9mm magazines
- Teflon finish ensures smoother operation and rust resistance
Cons:
- Does not accept Glock-style magazines
2. FoxTrot Mike Products AR-15 FM-9 Billet Stripped Lower Receiver
As a stripped lower receiver (other than the installed magazine release and bolt release), the FoxTrot Mike Products AR-15 FM-9 Billet Stripped Lower Receiver is ready to be customized out of the box. It’s a mil-spec design, meaning that it is compatible with other commonly available mil-spec grade AR9 parts.
Built out of aircraft grade aluminum and designed to accept Glock magazines, the FoxTrot has a last round bolt hold open feature to indicate when the magazine has run empty. This is a nice feature not standard on all AR9 lower receivers.
Features:
- Mil-spec design
- Built out of lightweight and durable materials
- Made out of 7076-T6 aluminum
- Built in the United States
- Has a last round bolt hold open feature
- Comes with a bolt release and magazine release pre-installed on the receiver
- Lifetime warranty from manufacturer
Pros:
- Ready for customization as a stripped lower receiver
- Compatible with Glock factory magazines
- Compatible with mil-spec components
Cons:
- Not assembled, so you’ll need to buy more parts
3. Palmetto State Armory PX9 Lower Receiver
The Palmetto State Armory PX9 is a fully assembled AR-15 lower receiver ready to install with a 9mm upper. Built out of aircraft-grade aluminum and coated in a rust-resistant black anodized finish, PSA specifically made the PX9 work with their hybrid 9mm uppers. The PSA enhanced polished trigger and SBA3 stabilizing brace are also welcome features.
This upper receiver is designed to work with factory 9mm Glock magazines. However, it is not intended to work with all aftermarket Glock magazines, so it’s up to you to test out any aftermarket magazines you have to see if they work.
Features:
- Built out of forged 7075-T6 aluminum
- Black hard coat anodized finish
- Comes with a PSA enhanced polished trigger
- Equipped with an SBA3 stabilizing brace
- Accepts factory Glock magazines
Pros:
- Already assembled
- Built out of lightweight and durable materials
- Excellent trigger pull
Cons:
- Does not accept all aftermarket Glock magazines
Conclusion
A high-quality AR9 lower like we have discussed here today can last you for a lifetime and be passed on down to future generations. Any of the lowers we have covered here today can be used to help build a new 9mm AR or otherwise upgrade your existing one.
Recommended Reading
Best AR-15 Calibers And Cartridges
3 Responses
You didn’t mention the aero precision epc9 lower
I use FoxTrot Mike lowers because they are built using 7075 T6 military grade aluminum and have last round bolt hold open. I use a Macon Armory buffer along with a 5.56 AR spring. This keeps bolt bounce to a minimum and by utilizing the 5.56 spring it does not hammer the bolt catch assembly when you run out of ammo. Macon Armory also makes barrels that are guaranteed to feed but I’ve also used Odin, Macon, Faxon, and Palmetto Armory. I usually try to mate a hand guard with my upper that has anti rotation tabs. I also use CMC 3.5 lb trigger assemblies as they are made strictly for 9mm.
Do you have a barrel for the AR9 for a 22TCM conversion?