5 Best AR9 Lower Receivers

This guide showcases the best AR9 lower receivers available right now

The lower receiver is as important as other parts of the gun. This is where the magazine goes, custom trigger group goes, and stock. This guide goes over the best ones on the market that's lightweight and ergonomical for PCC competition shooting and range training in general.

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AR9 Lower Receivers 101

Most AR9 builds are like LEGO parts like the AR. You can build small AR9 pistols, AR9 short barrel rifle or AR9 rifle in so many different ways. The receiver assembly is pretty much the same as AR with the trigger group being slightly different.

When building your 9mm AR9, Go with Glock mags. They're everywhere, and they won't break the bank. But if you're feeling adventurous, there are other options out there.

  • Durability: Look for strong materials like aircraft-grade aluminum.
  • Magazine Compatibility: Decide if you want Glock or Colt mags.
  • Finish: Make sure it's rust-resistant.

The lower receiver is defined as the "firearm" under ATF law, and it's a serialized part that requires 4473 background check at the time of purchase or transfer. It contains the firearm's control group (trigger, hammer, safety, etc.) and the buffer tube or receiver extension. 

  • For pistol with a brace setup, the gun will be considered as a pistol. No NFA paper filing or tax stamp required.
  • For AR9 short barrel rifle users, the gun is required for tax stamp and NFA registration. Either Form 1 or Form 4 (Click here to learn more)
  • For AR9 rifle builders, the gun is good to go

When you purchase an AR9 lower, even though it looks like it's just a gun part, you're buying a part that is defined as and treated as a "firearm." Therefore, it must be purchased like any other gun online and must go through an FFL.

If you want to buy a complete lower with the stock already installed, you can too.

Best AR9 Lowers

Aero Precision EPC 9

Aero precision EPC 9 lower receiver
  • Material: 7075 Aluminium
  • Construction Type: Forged
  • Weight: 12.8 ounces

Aero Precision EPC-9 lower receiver features easy to put in the takedown pin with a 4-40 screw. The large magwell helps the shooter insert the magazine smoother. It's made for short-throw safety selectors but works with regular ones too. You can adjust the fit between the top and bottom parts to make sure they fit tightly.

Aero Precision also makes various make AR accessories to go with your AR9 including optic mounts, lower receiver part kits and more. They make sure every product is top-quality for everyday shooters.

Pros and Cons

  • Works with 9mm and .40 S&W
  • Large magwell
  • Affordable


psa px9 lower receiver
  • Material: 7075 Aluminium
  • Construction Type: Forged
  • Weight: 8.5 ounces

The PSA PX9 receiver is meticulously machined from 7075 T6 aluminum and finished with a durable hard coat anodizing. Everything is built inhouse therefore the cost saving is huge for anyone building a 9mm AR.  the PSA PX9 is designed specifically for 9mm Glock®-style magazines. It's tailored to seamlessly integrate with Palmetto State Armory's 9mm uppers or other compatible 9mm uppers.

This lower receiver comes partially assembled, equipped with an unique magazine catch and ejector. It's all set and ready to be paired with your standard AR-15 lower parts, transforming it into a fully operational lower.

This AR9 lower receiver is designed exclusively for use with the Palmetto State Armory Hybrid 9mm Upper. Many PSA customers have shared their experience of pairing it with a PSA 4" 9mm lightweight M Lok 6" railed upper and other components, highlighting the overall length with the brace fully collapsed at about 21.5"

Pros and Cons

  • Simple
  • Very Affordable
  • No bolt lock on the last round

Foxtrot Mike Products FM-9 Billet Lower Receiver

fm9 stripped lower receiver
  • Material: 7075 Aluminium
  • Construction Type: Billet
  • Weight: 10.5 ounces

The Foxtrot Mike Products MIKE-9 9mm lower receiver is made from strong 7075-T6 aluminum. It fits with standard parts and works well with popular Glock magazines. Unlike many 9mm lowers, this one has a special feature that holds the bolt open after the last round. It comes ready with a trigger, safety switch, tube, grip, bolt button, and pins.

May not be California compliant. Please check with your local state law for more details

Pros and Cons

  • Ambidextrous design
  • Best QC in the Industry right now
  • Tight tolerance machining
  • Expensive

Angstadt Arms 0940 Lower Receiver

angstadt arms 0940 lower
  • Material: 7075 Aluminium
  • Construction Type: Billet
  • Weight: 10.2 ounces

The Angstadt Arms 0940 Lower Receiver is a masterpiece in design and functionality. With its wide, yet low-profile mag release, it ensures smooth operations without any snags. Pair it with your favorite spare AR9 upper, like the Palmetto State Armory 8 in upper, and experience seamless performance.

Its standout feature, the last round bolt hold open, sets it apart. The takedown pins, safety, and trigger are meticulously crafted for precision. Plus, it's compatible with mil-spec parts and comes with a pre-installed mag release for added convenience. Many Angstadt Arms 0940 customers rave about its impeccable finish, attention to detail, and the swift support from the company. 

  • Ambidextrous bolt release
  • Integrated trigger guard
  • Bolt locks open on the last round
  • Large magazine release

Spike’s Tactical Colt-Style 9mm Lower

ar9 spike tactical lower
  • Material: 7075 Aluminium
  • Construction Type: Billet

The Spike Tactical Colt style AR9 lower receiver reassembles the streamline design of any A2 style AR15. It works with battery assisted device like the Magpul BAD lever if preferred.

The build accepts 9mm Colt®-style magazines

Pros and Cons

  • Very tight fitting & premium quality
  • Bolt catch, large mag release paddle, take down pins & 45 degree safety lever pre installed
  • 9mm Colt®-style magazines maybe harder to find sometimes in most places

AR9 Receiver Parts To Avoid

Just because a part says "for 9mm" or "PCC" doesn't mean it's the best choice. Many are just products companies push out to profit without providing the full context on when and when not to use them. 

Here's a simple guide on parts you might want to think twice about:

Solid Buffer: It can make the bolt bounce and fire too early.

Captured Spring Systems: They make the bolt too light.

Hammers with a Notch in the Middle: They're old and not needed for 9mm. They might jam with new bolts.

Tiny Buffer Tubes: They're too short and don't work right with blowback.

Hammers with a Step at the Top: They're old and can make the bolt stick.

308 Recoil Spring: It's too strong for 9mm and can cause jams.

A5 Buffer Tube: Use with a long buffer and a buffer spacer.

Bolt Without a Bottom Feed Lug: It might fire the bullet too early.

Unramped Bolt: It's old and can break the hammer pin.

Light Hammer Spring: It might fire too fast.

Plastic Gun Body: They might break from the force. But some, like KE Arms, work if you use a 5.4 oz. buffer.

Triggers Made for 5.56mm AR-15: Only use if the maker says it's okay for PCC.

Short Buffer: Use with a buffer spacer or it might break parts.

Extra Strong Recoil Spring: Only use if you need a faster bolt for special triggers.

80% Receiver: Don't use. They can be tricky and might not work right if the user mill them incorrectly.

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