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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.

The Stern Mag-AD9 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.


Looking for a complete conversion kit?  We have you covered.
Click Here.

Already have a Colt Style bolt and want to use our system?  We have you covered.
Click Here

Don't Have a bolt, want one?  We have you covered.
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Don't Have a barrel, want one?  We have you covered.
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Technical Information:

⦁    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 Glock magazines.

⦁    Works with any mil spec ar15 lower receiver.

⦁     All gun components besides the Bolt and Barrel remain stock

Please visit the following link before purchasing to ensure compatibility with your setup.






48 Reviews Hide Reviews Show Reviews

  • 5
    MAG AD9

    Posted by Max on Jul 27th 2021

    Product is perfect. Vinyl adjustment screws make it a great fit. More importantly the customer service is outstanding. Highly recommend.

  • 5

    Posted by Duckstreet on Jul 27th 2021

    Works great!

  • 5

    Posted by Robby T on Jul 14th 2021

    Great product. I put this in my lower using a PSA 9 upper with Glock style BCG, and went at it. No jams at all. I was using the SD HB1-H3 BUFFER and it cycled great. The bolt release was a little stiff at first, but after a couple of mag changes, it loosened up. If you don't want to buy a dedicated 9mm lower, this is a great product. It's also a bonus that you don't have to use an FFL, as you would with a lower.

  • 5
    Stern Defense MAG-AD9

    Posted by Racky on Jun 7th 2021

    Installed this in my Eagle Arms lower. Tactical Solutions 16” barrel. Faxon Bolt. Magpul GL-9 mags. This thing rocks ran like a sewing machine not one hiccup.

  • 5
    Works Great

    Posted by Bobby on May 17th 2021

    Fits perfectly in my Anderson Hellfire lower. Highly recommend.

  • 5
    Stern 9mm conversion

    Posted by Mitchell Davis on May 4th 2021

    Easy install. Works great. Feeds great.

  • 5

    Posted by Drew on Apr 26th 2021

    Cycles perfectly, once you set it up it stays in place through a tons of rounds, haven’t had to readjust since I got it!

  • 5

    Posted by William Palacio on May 25th 2020

    There were 2 of this product one of them is from Stern Defense the MAG-AD9. After much search and compare its product. I found that the Stern was suited for my own liking compare to the other one I was looking into. When I finally received the MAG-AD9 I was impress if the quality that it's made from. I test fitted it I was happy with it glad I bought this from Stern. Great addition to my new AR9.

  • 5
    Mag Well Adapter - Am I nuts?

    Posted by RoCo on May 15th 2020

    First thoughts after unboxing. This thing costs more than some dedicated lowers. Am I nuts?
    After i popped this into my lower with a specialty trigger, I felt a whole lot better! This thing is real....and I didn't have to buy a new lower, or trigger, etc, etc.
    LRBHO is awesome. Fit and function are perfect.