New Products

Stern Defense Mag-AD Magazine Adapters

  • Compatible Glock, M&P, and Beretta magazines
  • Fits in any MilSpec AR-15 lower
  • Ergonomic magazine release button

So you want to lob pistol caliber projectiles from your AR but don’t want to have to buy a dedicated lower receiver in order to do so. No sweat. As you might be aware already, there are plenty of magazine well adapters available on the market designed to help convert your .223 Rem/5.56 NATO sized AR-15 magwell to one sized perfectly to accept pistol caliber magazines

Over the years, we’ve messed around with our fair share of different AR-15 pistol caliber magazine adapters and found some of them to be garbage but many more of them to be more than adequate at performing the job that they were designed to do; which is, get pistol caliber ammunition to reliably feed in an AR-15 platform rifle. Most if not all of those adapters however, used Colt-pattern or modified Uzi magazines. While not exactly endangered species, Colt and Uzi mags aren’t commonly found in most gun owner’s magazine collections either. 

In more recent times, AR’s that feed off of Glock magazines have become much more common and universally embraced by pistol caliber AR shooters. The fact that your pistol and carbine can feed the same ammunition from the same source is a desirable trait to many for obvious reasons. 

When Glock magazine capable AR’s were first introduced however, they required dedicated lower receivers. Since then, companies have released magazine adapters that can be installed in a standard AR-15’s magwell to allow them accept Glock magazines. This is where Stern Defense steps in. 

In an attempt to perfect their magazine adapter, Stern took a look at what worked, what didn’t and what could use improvement. The Mag-AD series of magazine adapters were born. After being able to handle and use the Mag-AD, it occurred to us that Stern didn’t set out to simply improve magazine adapters, but wanted to make all the other adapters that came before it obsolete. 

Unlike most of the mag adapters that we’ve seen before, the Mag-AD checks all the boxes of what we’re looking for. Other adapters that we’ve used in the past have required bolt catch removal or other partial disassembly of the lower receiver for installation. The Mag-AD on the other hand is not permanent and simple to install, requiring only two Allen keys to screw in three setscrews. In fact, we were able to install the adapter in about a minute tops. Two smaller setscrews help with the positioning of the adapter inside the magwell while the largest of the three setscrews tightens an internal wedge piece that helps secure the adapter so that an inadvertent push of the lower receiver’s mag release button doesn’t dump the adapter out. The adapter works with any standard MilSpec lower receiver.

If you want to switch back to having access to your regular magwell, you can uninstall the adapter by simply loosening the larger setscrew and then pressing the mag release button to release it like you would when ejecting a magazine. The adapter is made in the U.S.A. and is constructed from hard coat anodized Type III 6061-T6 aircraft grade aluminum. We found the machine work to be clean with nice finished edges and no evidence of machining marks. The Mag-AD’s feed ramp has been thoughtfully 4140 NiB coated to help bullets feeding smoothly.  

In addition to its easy and solid installation, there are three more attributes that we absolutely love about the Mag-AD. The first is that it features a no-hassle last round bolt hold open feature. We’ve had to tangle with other pistol carbine builds in the past where getting the bolt to lock back on an empty mag was all trial and error. In our experience with the Mag-AD, the mag locked back reliably without any need for tuning the mag ejector. 

Another factor that stood out to us was its well-placed magazine release. Located on the bottom of the right side of the adapter, at a perfect distance to the trigger finger, is its magazine release button. The ergonomic mag release is pushed forward to release a magazine and has a solid, positive feel to it. Of course, this is from the viewpoint of a right-handed shooter. Lefties or those shooting with their off hand would probably need to use their right hand to eject the magazine.

As mentioned earlier, the Mag-AD is made to accept Glock magazines, specifically 9mm and .40 caliber magazines of all generations. We’re pleased to mention that Stern went the extra mile and also made versions of the Mag-AD that accept Smith & Wesson 9mm and .40 caliber and Beretta 92 9mm magazines as well. Being M&P fans, we rejoiced in being able to use our existing M&P mags with our 9mm AR-15. 

In order to use the Mag-AD, a pistol caliber upper is required. Stern points out that the adapter requires your choice of a 9mm or .40 caliber barrel and a compatible Glock cut-style bolt. For those who have a Colt style bolt, you can even send it to them to get it cut. 

We had the chance to use both the Glock and M&P versions of the Mag-AD with a wide selection of magazines from different manufacturers and generations. Each of the magazines we used worked and we detected only minimal play in the fit of certain magazines. Overall, we were extremely pleased with the design, feel, function and look of the Mag-AD. If Stern wants to make this the end all, be all adapter, we think an ambidextrous solution would be a great addition to an already feature packed unit. But as it stands now, it looks as if Stern may have produced the magazine adapter to beat. 

PQs:

“The fact that your pistol and carbine can feed the same ammunition from the same source is a desirable trait to many for obvious reasons. “

“After being able to handle and use the Mag-AD, it occurred to us that Stern didn’t set out to simply improve magazine adapters, but wanted to make all the other adapters that came before it obsolete.”

“Unlike most of the mag adapters that we’ve seen before, the Mag-AD checks all the boxes of what we’re looking for.”

“Overall, we were extremely pleased with the design, feel, function and look of the Mag-AD.”

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