Stern Defense makes great AR magazine well adapters. With one of Stern’s adapters, you can turn your AR Lower into a Pistol Caliber Carbine that accepts Glock magazines (9mm/.40). They didn’t stop there. They also make adapters for Beretta Magazines (9mm), S&W M&P magazines (9mm/.40) and another S&W M&P model which uses .45 ACP. Mag-AD series adapters install in seconds, just like an AR magazine. They have a separate magazine release at the bottom you manipulate with your trigger finger and a functioning last round bolt hold open feature.

I have worked with several similar systems. The big question; Do they work? I got to shoot one at TriggerCon and I watched hundreds of rounds go through it. The Stern adapter fits snugly and it runs smoothly. Of course, you have to select the correct upper and buffer to make these guns run, but now you don’t have to build a dedicated lower. Stern has a web page you can check before purchasing to ensure compatibility with your setup so you don’t buy parts that don’t fit together.

Pistol caliber ARs are cheap plinkers and great training tools perfect for new shooters. You can safely shoot handgun steal and use the magazines you already have. Law Enforcement agencies can build an AR that accepts their duty pistol mags for the ultimate police patrol rifle.


Stern Defense Magwell Adapters: Turn Your AR Lower into a Pistol Caliber Carbine
The Stern Defense MAG-AD9 uses 9mm and .40 S&W Glock Magazines!

The Stern Mag-AD9 series adapters are made of aircraft grade aluminum, lightweight with ergonomic design. There is a tension adjustment feature to eliminate wiggle.

The Stern Defense MAG-ADMP45 use 45ACP M&P Magazines

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 any mil spec ar15 lower receiver.

⦁     All lower components besides the adapter remain stock





The MAG-AD9 system is not compatible with New Frontier, PSA Hybrid or Foxtrot Mike bolts. This is due to the lug which strips a round off of the magazine being .035 of an inch further from center-line as compared to other bolt systems. If you are looking to use these bolts with our system we will provide bolt modification services with the purchase of a mag-ad9. More info HERE.

Stern Defense Magwell Adapters: Turn Your AR Lower into a Pistol Caliber Carbine
This is the converted 9mm AR I shot at TriggerCon

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

Already have a Colt Style bolt and want to use their system?  They have those too.
Click Here

Don’t Have a bolt, want one?  
Click Here

Don’t Have a barrel, want one?  
Click Here

You can get your very own Stern Defense Magwell Adapters HERE. MSRP $179

About Stern Defense:

STERN DEFENSE is a family owned American specialty manufacturer committed to precision, quality, and efficiency of the weapon accessories created. They use the best USA supplied material our products are designed and manufactured by the finest machinists and engineers in the industry.

Stern Defense Magwell Adapters: Turn Your AR Lower into a Pistol Caliber Carbine
The family behind Stern Defense

Their values? Traditional, Rooted, Firm and STERN.