In stock
Stern Defense AR-15 Mag Well Adapter for M&P 9mm/40S&W, Black- MAG-ADMP9&40
In stock

Stern Defense AR-15 Mag Well Adapter for M&P 9mm/40S&W, Black- MAG-ADMP9&40

SKU 5165490971
Brand Stern Defense
Model Number MAG-ADMP9&40
UPC 850001176217
Customers must read Compliance Information before purchasing.

Product Details


  • Brand: Stern Defense
  • Model: Mag Well Adapter
  • Fits: M&P 9mm and 40  S&W
  • Material: 6061 T6 aircraft grade aluminum
  • Finish: Hard coat anodized type 3
  • **Must be used with a 5.4 oz. buffer or heavier when using a carbine spring


Convert your standard mil spec AR 15, M4, M16 lower assembly to use 9mm and .40 S&W M&P and P320/P250 Magazines! The Mag-AD series adapters install in seconds. Boasting a last round hold open feature making them a breakthrough product and a must-have for law enforcement and civilian gun enthusiasts alike. The Stern Mag-AD series adapters are made of aircraft grade aluminum, lightweight with ergonomic design.

Note: These adapters require the use of a 9mm or 40S&W barrel, "depending on chosen caliber" and a Glock cut bolt.


  • Made in the U.S.A.
  • Constructed from 6061 T6 aircraft grade aluminum.
  • 4140 NiB coated feed ramp.
  • Hard coat anodized type 3.
  • Sturdy Construction.
  • Ergonomic mag release.
  • Works with all generations of M&P magazines.
  • Works with P320 and P250 magazines
  • Works with any mil spec AR-15 lower receiver.
  • All gun components besides the Bolt and Barrel remain stock


Q & A

Retail Stock


All NFA Rules Apply.
These items are controlled by the U.S. Government and authorized for export only to the country of ultimate destination for use by the ultimate consignee or end-user(s) herein identified. They may not be resold, transferred, or otherwise disposed of, to any other country or to any person other than the authorized ultimate consignee or end-user(s), either in their original form or after being incorporated into other items, without first obtaining approval from the U.S. government or as otherwise authorized by U.S. law and regulations.