Stern Defense Mag-AD9 AR-15 9mm/.40 S&W Magazine Adapter

Description

The Stern Defense Mag-AD9 converts a standard mil-spec AR-15 lower configured for 5.56mm to accept 9mm and .40 S&W magazines for S&W M&P and SIG P320/P250 platforms. The adapter is made in the USA and is identified by SKU 001SDMAGADMP9AND40/P32.

Designed for straightforward installation, the Mag-AD9 retains the standard AR-15 lower receiver while providing an ergonomic magazine release and last-round hold-open feature. The adapter works with all generations of S&W M&P magazines and with SIG P320 and P250 magazines.

Key Specifications

• The compatible cartridges are 9mm and .40 S&W.
• The adapter is designed for a standard mil-spec AR-15 lower configured for 5.56mm.
• The compatible magazine platforms are S&W M&P and SIG P320/P250.
• The body is constructed from 6061-T6 aircraft-grade aluminum.
• The finish is Type 3 hard-coat anodized.
• The feed ramp features a 4140 nickel-boron coating.
• The listed dimensions are 3.45 × 4.40 × 8.65 inches.
• When used with a carbine spring, the adapter requires a 5.4-ounce buffer or heavier.
• The product is made in the USA.
• The UPC is 850001176217.

The buffer is not included, and the adapter requires a Glock-cut bolt. All firearm components besides the bolt and barrel remain stock according to the supplied product information. Direct shipment to California is not available.

With its aluminum construction, hard-anodized finish, broad M&P and P320/P250 magazine compatibility, and AR-15 lower integration, the Mag-AD9 provides a practical platform-conversion component for compatible builds.

Specifications