I now have 3 of these adapters and have not had a single malfunction. Works perfect in my AR9 and AR45 pistols.

Shipping was fast.
Very easy to install and worked perfectly on a select fire lower. Runs fast and reliable!
Recommend to anyone looking to covert an ar15 lower to a reliable 9mm carbine!

Went together perfectly and functions flawlessly.

I was very impressed with this product. After trying various different 9mm receivers that would not run enhanced fire groups I saw a video of this one running on youtube. I decided to try this one. It works perfectly with all trigger that were tried . I have yet to have a malfunction as to date ! This is a little pricey, but worth every dime. I love the ability to switch from 9mm to 5.56 with the same lower. Just buy it , you will not be disappointed. Also I would suggest buying a PSA lower for this adaptor . It is a perfect marriage. Locks back every time !

This is an amazing product, so amazing that I now own two of them. I looked into the competitors similar product, I even have friends that own the competitors product, there is no comparison. Yes, you somewhat get the same end result from both products, but it's worth the few extra dollars to buy from Stern Defense. Last round hold open, better placement of the mag release, solid lockup, what else is there to say. I have experienced ZERO issues running this adapter in my setup, and I'm currently at 1,000 + rounds through my PCC. I'm a farmer in the high desert region of MT. It's quite dusty, and we experience extreme temperature changes. My PCC is my go to for when I'm running around on the quad doing farm stuff, and I run Stern Defense on that PCC. Don't want to spend the extra money? Be prepared to be disappointed. Thank you, Stern Defense!

I've built several dozen AR platform rifles and pistols over the last decade, many of them as PCCs. I've now built two 9mm AR-15 pistols using the MAG-AD9 adapter, and for my money, it's the absolute best way to go, no doubt. The Stern Defense adapter is far superior to all its competitors, too. The thing is not just well-built, it's rugged in the extreme. Using this adapter in a standard AR-15 lower gives you the flexibility to keep your AR-15 instantly ready for use as a conventional caliber weapon, be it a 5.56mm, .300 BLK., or any other chambering. This is a huge consideration for folks who are limited in only being owning a single AR rifle or pistol. In addition, the last round hold-open is drop-dead reliable, too (and if yours doesn't work, blame the magazine). The MAG-AD9 is the best way to go no matter what, even if you intend to use your weapon as a dedicated 9mm rifle, carbine or pistol.

Awesome build quality. Have ets 32rnd Glock mags which fit/ function perfectly. Zero complaints, would recommend

So far is the best conversion block than others, Thanks Stern!!

Excellent quality and am headed to range this week with it. Pricey but you get what you pay for. Fit and finish superb and the shorty upper is exactly what I've waited for.