Reviews & Ratings for Guntec USA AR-15 9mm Magwell Adapter Block — 7 reviews — Page 1

I have two of these adapters and have had zero issues with them. One is installed in a 10.5" pistol with PSA lower, PSA gen2 BCG, and PSA Barrel. The other adapter is installed in a 16" carbine with PSA lower, Faxon BCG, and Faxon barrel. Using 4, 20rd C products and 5. 32rd C products mags, These mags fit and function perfectly. DO NOT USE ProMag magazines. They are junk. do not fit in the adapter way too tight and feed lips scrape the bottom of the BCG.

I bought this because it is cheap and decided why not try it. After install the BCG does not slide over the feed lips. Even after filing .05” off the feed lips it does not slide over. Mags have a lot of play. You have the smash the mags in just to get them into the mag catch. I even tried filing one of my mags to get it to work but that resulted in my mag not holding the last 2 rounds so now the mag is junk.

Received this item and the package had already been opened. Huge red flag there. Installed in 3 different mil spec. Lowers and magazines (Metalform) would not lock up. The problem being the magazine stop built into the feed ramp holds the magazine too low. So instead of returning this to Optics Planet, like I should have, I did some fitting. After raising the feed ramp, the mags locked in with the adapter installed but when I tightened up the two set screws the magazines would no longer lock up. Adjust, adjust, adjust. Finally get the thing installed and the mags lock up. After firing a few times, the adapter moved and lock up went away. Remove the set screws and everything works. Problem is the adapter is loose in the magwell, and the mags fit extremely tight in the adapter. So $90 for a mediocre mag block that doesn't fit worth a darn. My other mag block is one of the cheap ProMag ones (currently under $50) and it is FAR superior if installed as a one piece top load block. So save your money, buy the ProMag one. Yes, it's plastic and has a stamped feed ramp. But it drops in and works. I do NOT recommend taking it apart and installing it through the bottom. Pull the bolt hold open and drop the whole thing in assembled from the top. It also doesn't need set screws to bugger up your magwell.

Great product 5 stars but optics planet had very slow shipping and very confusing tracking. 10 days to go from Illinois to Tennessee take two days off for weekend so 8 days. Product works well and inserted to a perfect fit. No instruction came with it but it was a simple install. Remove one screw and insert adapter then place three screws and your good. Maybe COVID is the only problem with shipping.

These are GREAT ! Fit and finish are excellent and they work exactly as advertised. I have built two 9mm Colt clones because I really like that classic smg look. The Guntec adaptors are offered at a really good price and the bonus is if you ever want to change back they are easily removable. Not that you would ever want to cause they are so much fun.