Unleash a new kind of firepower
Built to Run. Made to Fit. Engineered for you.
The AUTO 20 is a purpose-built, mag-fed 20-gauge upper that turns any standard AR-15 into a lightweight, low-recoil smoothbore with real stopping power. Designed around a proprietary polymer shell system, it offers the control, speed, and familiarity of your favorite rifle, with a payload that changes the equation. No adapters. No compromises. Just plug in and shoot.
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WHAT SETS THE AUTO 20 APART
AUTO 20 TECHNICAL SPECIFICATIONS
UNLEASH THE POTENTIAL OF YOUR AR-15
Technical Specifications
- Gauge: 20-Gauge
- Compatible Platform: Any AR-15 Lower Receiver
- Chamber: 2¾" Shells
- Barrel Length: 16 inches
- Overall Length: Approximately 25.5 inches
- Weight (Unloaded): ~5.9 lbs
- Barrel Type: Smoothbore
- Choke Compatibility: Threaded (Rem-Choke compatible)
- Receiver Material: Billet Aluminum
- Finish: Hardcoat Anodized
- Action Type: Semi-Auto
- Operating System: Direct Impingement
- Magazine Type: Detachable Box Magazine
- Magazine Capacity: 7+1 (Standard), Extended Options Coming
Included Components
- Complete 20-Gauge Upper Receiver Assembly
- Proprietary Bolt Assembly
- No Additional Buffer or Spring Required
- One 7-Round Magazine Included
- Owner’s Manual / Installation Guide
- Threaded Choke Tube and Wrench
Testing & Compliance
- Tested with Butler Defense Polymer 20-Gauge Shells
- Meets Rigorous Performance and Cycling Standards
- Compliance Notes: Upper receiver only; not classified as a firearm under federal law*
Installation & Compatibility
- Installation Time: Under 2 minutes
- Tools Required: None (standard AR push-pin installation)
- Warranty: 1-Year Limited Warranty
- Made in: Sun Valley, Idaho, USA
compatible with any standard ar-15 platform
enhance your AR without compromising its integrity
Whether you’ve got a bone-stock lower or a tricked-out billet build, the AUTO 20 gives you seamless integration and a completely new ballistic profile, without giving up what you already love. No recoil surprises. No compatibility curve. Just smooth, confident operation in a platform you already trust. It’s a full upper receiver system that bolts directly onto any AR-15 lower, without tools or tuning. No touching your buffer system or trigger group. Push two pins, lock it in, and it’s ready to run.
It’s not a bulky conversion or a clamshell workaround. Everything from the bolt geometry to the magwell interface is designed with the AR platform in mind, not retrofitted from an off-the-shelf shotgun. Your safety, selector, trigger, grip, and stock stay exactly where they are. And because the lower remains untouched, it still feels like your AR: intuitive, modular, and ergonomic.
POWERED BY PRECISION ENGINEERED CUSTOM SHELLS
Proprietary. Proven. Powerful.
The AUTO 20 runs on its own system, built around a proprietary 20-gauge shotshell, developed specifically for semi-automatic cycling in a magazine-fed AR-style platform. It’s custom-engineered and built to solve real problems: feeding geometry, ejection reliability, weight, pressure, and heat.
At the heart of it is a durable, high-strength polymer hull, designed to resist deformation, tolerate rapid cycling, and shed heat far better than brass or aluminum. Every angle, rim, and taper has been optimized to work with the AUTO 20’s internal architecture, from chamber to extractor. The result is a shell that loads fast, ejects clean, and hits hard, shot after shot.
And because it’s proprietary, it allows for performance tuning that off-the-shelf ammo just can’t touch. The payload, pressure curve, and wall thickness are all engineered in parallel with the platform itself. That means no surprises, no stovepipes, and no compromises. Just consistent, reliable firepower built into the DNA of the system.
What shooters are saying
“I’ve shot just about every type of shotgun out there, and the AUTO 20 holds its own. lt feels solid, there’s zero rattle, and it cycles smoother than some of the most expensive automatics on the market.
Aaron, Professional Shooter
. “As someone who spent over 20 years training with the AR, the AUTO 20 is just about the perfect home defense tool. No worries about overpenetration, just effective, controllable firepower on a familiar platform when it matters.”
Eric, Veteran
“It’s light, snappy, and ridiculously fun. First time I tried it, I was smiling like a little kid. I’m also not that strong, and it doesn’t beat me up like a 12-gauge. I could honestly shoot it all day. ”
Victoria, Lifelong Enthusiast