Nice looking and well built, now only if it worked... - Guntec USA AR-15 9mm Magwell Adapter Block

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.