Stern Defense Mag-AD9 Magazine Adapter for AR-15
Convert your AR-15 lower to use Smith & Wesson M&P and Sig P320 magazines in 9mm and .40 S&W. Aircraft-grade aluminum construction with last-round hold-open feature.
Fits: AR-15
Stern Defense Mag-AD9 Magazine Adapter
Transform your standard mil-spec AR-15, M4, or M16 lower receiver into a capable 9mm or .40 S&W platform using common Smith & Wesson M&P and Sig P320/P250 magazines.
Key Features
- Quick Installation: Adapter installs in seconds without gunsmithing
- Last Round Hold Open: Magazine runs empty and bolt locks back—a critical feature for training and duty use
- Durable Construction: 6061-T6 aircraft-grade aluminum with hard-coat anodized Type 3 finish
- Reliable Feed Path: 4140 NiB-coated feed ramp ensures consistent reliability
- Magazine Compatibility: Works with all generations of M&P magazines and P320/P250 magazines
- Ergonomic Design: Smooth magazine release for efficient reloads
- Made in the U.S.A.
What You Need to Know
The Mag-AD9 lets you repurpose your existing AR-15 lower receiver for pistol-caliber shooting. All standard components—bolt carrier group, charging handle, stock, and furniture—remain unchanged. This adapter is an excellent solution for shooters who want a dedicated 9mm or .40 S&W platform without purchasing a complete new rifle.
Whether you're building a training gun, a home-defense carbine, or exploring pistol-caliber rifle shooting, the Mag-AD9 delivers proven reliability and practical functionality.
