![Stern Defense MOD4 9mm Luger 4" Complete Upper Receiver Glock Black Stern Defense MOD4 9mm Luger 4" Complete Upper Receiver Glock Black](https://cdn11.bigcommerce.com/s-5qn5r1bnl8/images/stencil/300x300/products/2513/4268/stern_defense_mod4_upper__53234.1712262711.jpg?c=1)
This is a new Stern Defense MAG-AD9 magazine well adaptor compatible with AR pattern firearms chambered in 9mm Luger. Convert your standard mil spec AR 15, M4, M16 lower assembly to use 9mm and .40 S&W Glock 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.
Note: These adapters require the use of a 9mm or 40S&W barrel, "depending on chosen caliber" and a Glock cut bolt. THIS MUST BE USED WITH A 5.4 OUNCE BUFFER OR HEAVIER WHEN USING A CARBINE SPRING.