Stern Defense Mag-AD9 Magazine Adapter 9mm/40 S&W Sig P320/P250

The Stern Defense Mag-AD9 transforms Sig P320 and P250 pistols into versatile platforms capable of accepting standard 9mm and .40 S&W magazines. This aircraft-grade aluminum adapter eliminates the need for proprietary magazines while maintaining reliable feeding and ejection across multiple calibers.

What Makes This Different

Unlike basic magazine wells that only improve grip and reload speed, the Mag-AD9 actually changes magazine compatibility. The precision-machined aluminum construction ensures consistent magazine seating and proper cartridge presentation to the chamber. Standard polymer adapters often flex under pressure, but aircraft-grade aluminum maintains dimensional stability through thousands of rounds.

Key Features

• Aircraft-grade aluminum construction for maximum durability and precision
• Compatible with Sig Sauer P320 and P250 pistol frames
• Accepts both 9mm Luger and .40 S&W magazines
• Black anodized finish resists corrosion and wear
• Precision-machined tolerances ensure reliable magazine retention
• Drop-in installation requires no permanent modifications
• Maintains original trigger group and safety systems

Competitive shooters and law enforcement officers benefit from standardized magazine compatibility across different platforms. The adapter maintains proper magazine angle and spring tension for consistent feeding. Weather resistance comes from the Type III hard anodizing that protects against moisture, salt, and temperature extremes. Range testing shows reliable function with both ball and hollow point ammunition.

Technical Specs

• Material: Aircraft-grade aluminum alloy
• Finish: Type III hard anodized black
• Compatible Firearms: Sig P320, P250 series
• Supported Calibers: 9mm Luger, .40 S&W
• Installation: Drop-in, no gunsmithing required
• Weight: Approximately 2.1 ounces
• Country of Origin: United States

The Mag-AD9 represents a practical solution for shooters seeking magazine standardization without compromising reliability. Professional armorers and serious enthusiasts recognize the value of quality materials and precise manufacturing in critical components.