The personal defense weapon you can build at home.
Pistol caliber carbines have seen a massive rise in popularity as backpack guns, vehicle defense tools, and personal defense weapons (PDWs) — and it’s easy to see why. A shouldered 9mm gives you rifle-like accuracy with handgun-level recoil, making it easier to shoot well under stress than any pistol. Compared to a 5.56 rifle, a 9mm PCC produces less muzzle blast, less concussion, and dramatically less over-penetration through interior walls — exactly what matters when your family is on the other side of them.
Modern folding stocks and braces make a PCC compact enough to stow in a backpack or behind a truck seat. You get 30+ round capacity, share ammunition and magazines with the 9mm handgun you already carry, and cut your training logistics in half. With subsonic loads it’s also one of the quietest platforms you can suppress.
As of January 2026, the federal SBR tax dropped from $200 to $0 — meaning there has never been a better time to build a short-barrel 9mm PCC for personal defense. The A9X is 80% Arms’ first Colt-pattern AR-9 lower, designed from the ground up for builders who want the magazine platform that was actually built for this job.
This SKU includes internal hardware — ready to install after milling:
- Black nitrided steel feed ramp with integrated magazine stop
- Steel ejector
- Ambidextrous bolt release hardware
Colt® Pattern vs. Glock® — Why It Matters
✘ Glock® Pattern
- Designed for pistol-length actions
- Single-column feed geometry
- Rounds can unseat under blowback recoil
- Cheap and everywhere — but built for a different job
✔ Colt SMG Pattern (A9X)
- Purpose-built for submachine guns
- Double-stack, double-feed design
- Grips top cartridge tighter under harsh cycling
- Seats naturally, indexes faster on reloads
If your AR-9 is more than a range toy, Colt pattern is the platform it should run.
Features
- Ambidextrous bolt release — Mirrored controls on both sides. Ambi hardware included in the box.
- Last-round bolt hold open — Locks the bolt back on empty with a Colt-pattern AR-9 bolt catch. No guessing whether you’re dry.
- Steel feed ramp with integrated magazine stop — Black nitrided for durability. Keeps feeding smooth and consistent, round after round. Included.
- Steel ejector — Dependable ejection every shot. Included and ready to install.
- Flared & curved magwell — Faster, more forgiving reloads under stress. Shaves weight and improves grip angle.
- Threaded bolt catch screw — No roll pin headaches. One of the most common AR-9 build frustrations, solved.
- Full AR-15 parts compatibility — Your trigger, safety, grip, buffer tube, and takedown pins all drop in. No vendor lock-in.
- Compatible with most AR-9 uppers — Works with Colt® or Glock® magazine feed geometry uppers.
- Oversized winter trigger guard — Gloved use without fighting the guard. Integrated, not bolt-on.
- Matte Black Type III anodize — Mil-spec hard anodize for corrosion resistance, wear protection, and a clean matte finish that’s ready for duty out of the box.
- 5-axis CNC machined from solid billet — Every A9X starts as a single solid block of 6061-T6 aluminum and is precision-cut on a 5-axis mill in Fort Worth, Texas. Billet delivers a tighter grain structure, zero porosity, and tolerances that give you a noticeably better upper-to-lower fitment. It also gives our engineers the design freedom to integrate features like the flared magwell and oversized trigger guard directly into the receiver — carved from one piece, not compromised by a die.
- Easy Jig® compatible — Works with Easy Jig® Gen 2, Gen 3, and Gen 4. Not compatible with Easy Jig® Gen 1 or Universal Drill Press Jig.
Why Build an AR-9?
You’ll hear people say the AR-9 is obsolete now that roller-delayed and gas-delayed PCCs exist. Here’s what they leave out: those platforms start at $1,200+ as factory-complete guns. You can’t build them at home. You can’t swap your own trigger. You can’t choose your own barrel length, handguard, or furniture.
The direct-blowback AR-9 is the only 9mm PCC platform you can build from scratch with standard AR-15 tools and parts, customize exactly the way you want, and maintain with components available at any gun shop in America. Simpler action, fewer proprietary parts, decades of proven reliability.
Ships when production is complete. You won’t be charged until it ships.
Complete Your Build
Machine it. Install parts. Mate your upper. Here’s what you need:
| Finishing Jig | Compatible with Easy Jig® Gen 2, Gen 3, and Gen 4 |
| A9X Internal Parts | ✔ Included — steel feed ramp, steel ejector, and ambi bolt release hardware ship in the box |
| Lower Parts Kit | AR-15 Mil-Spec LPK — standard kit works |
| Buffer Tube Kit | AR-9/45 Carbine Buffer Tube Kit |
| Magazines | Duramag Colt SMG 9mm (20rd & 32rd) |
| Upper & Kits | Browse AR-9 Uppers & Kits → |
Specifications
| Material | 6061-T6 Billet Aluminum |
| Magazine Compatibility | Colt® SMG 9mm (double-stack, double-feed) |
| Upper Compatibility | Most AR-9 uppers designed for Colt® or Glock® magazine feed geometry |
| Lower Parts Compatibility | Standard mil-spec AR-15 (triggers, grips, safeties, detents, takedowns) |
| Included Hardware | Black nitrided steel feed ramp w/ magazine stop, steel ejector, ambi bolt release hardware |
| Jig Compatibility | Easy Jig® Gen 2, Gen 3, Gen 4 — not compatible with Gen 1 or Universal Drill Press Jig |
| Finish (This SKU) | Matte Black Type III Anodize — also available in Raw, Cerakote, and Stripped |
| Controls | Ambidextrous bolt release compatible |
| Made In | Fort Worth, Texas, USA |
Common Questions
What jig do I need to finish this lower?The A9X is compatible with Easy Jig® Gen 2, Gen 3, and Gen 4. It is not compatible with Easy Jig® Gen 1 or the Universal Drill Press Jig. Contact us at support@80percentarms.com if you’d like to confirm compatibility with your specific setup before ordering.
This SKU ships with the steel feed ramp, steel ejector, and ambi bolt release hardware already in the box. In addition to this 80% lower and the included hardware, you’ll need: a compatible Easy Jig® (Gen 2, 3, or 4), a standard AR-15 lower parts kit, a buffer tube kit (we recommend the AR-9/45 Carbine Buffer Tube Kit), an AR-9 complete upper, and Colt-pattern 9mm magazines. See our Complete AR-9 Build Guide for step-by-step instructions.
An 80% lower receiver is a partially completed receiver that is not yet classified as a firearm by the ATF. It requires additional machining (which you do at home with a jig) to become a functional lower. Building a firearm for personal use is legal in most states and does not require an FFL transfer — the product ships directly to your door. Check your state and local laws before purchasing. See shipping restrictions below for states where we cannot ship this product.
As of January 2026, the federal tax on short-barreled rifles (SBRs) and suppressors is $0. The ATF registration process (Form 1 for manufacture) is still required — you’ll still submit paperwork, fingerprints, and a photo — but there’s no longer a $200 fee. This makes short-barrel AR-9 builds significantly more accessible. If you’re building a pistol configuration with a brace, no NFA registration is required at all.
LRBHO (Last Round Bolt Hold Open) locks the bolt to the rear when the magazine is empty, giving you a visual and tactile confirmation you’re out of ammo. The A9X supports LRBHO when paired with a Colt-pattern AR-9 bolt catch. This SKU includes the bolt catch hardware — it installs into the threaded bolt catch screw hole. Read our full LRBHO explainer here.
Yes. The A9X accepts standard mil-spec AR-15 fire control groups. Single-stage, two-stage, drop-in cassette triggers — they all work. If it fits a standard AR-15 lower, it fits the A9X. No proprietary trigger required.
Most AR-9 uppers are designed to work with either Colt® or Glock® magazine feed geometry. The A9X is compatible with both types of uppers. The key difference is at the magazine — the A9X uses Colt®-pattern magazines regardless of which upper you pair it with.
AR-9 direct blowback builds require a heavier buffer than standard AR-15 builds — typically 5-8 oz. Our AR-9/45 Carbine Buffer Tube Kit comes with the correct buffer weight for 9mm. If you’re using a standard carbine buffer tube, you’ll need to source a 9mm-specific buffer separately.
Absolutely. 9mm AR builds are one of the most popular suppressor host platforms. The A9X works with any suppressor-compatible AR-9 upper. You may want to experiment with buffer weight to tune the cycling when running suppressed, as back pressure can increase bolt velocity. With the $0 SBR and suppressor tax stamps, a short-barrel suppressed 9mm build is more accessible than ever.
Pre-orders ship in order received once the first production batch is complete (estimated spring 2026). You won’t be charged until your order ships. Pre-ordering reserves your unit from the first batch — once that allocation is filled, the next batch goes into the production queue. Contact us for the latest timeline.
Lifetime Warranty
80% Arms stands behind this lower with a lifetime warranty against manufacturing defects. If something isn’t right, we make it right. Contact us at support@80percentarms.com, call (949) 354-2767, or use live chat.
This item cannot be shipped to: California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Maine, Maryland, Massachusetts, Nevada, New Jersey, New York, Oregon, Rhode Island, Vermont, Washington, Washington D.C., Philadelphia, York City, Reading Pennsylvania, Delaware County Pennsylvania.
Under California law this product is or contains an unserialized firearm precursor part and cannot be sold into the State of California. 80% Arms cannot accept orders of this product for shipment to California or to customers who are residents of California.
Colt® is a trademark of Colt’s Manufacturing Company LLC. Glock® is a trademark of GLOCK, Inc. This is an aftermarket product and is not produced by, endorsed by, or affiliated with Colt’s Manufacturing Company LLC or GLOCK, Inc. All trademarks are used strictly to indicate compatibility.
