I mounted a $20.00 red dot scope and a quick release 4 slot 1 inch riser onto my 9mm Kel-Tec sub 2000. Yesterday, I went to the range and shot the gun to see if the scope would returned back to zero after the scope was removed and then remounted. It did not return to zero, elevation was good, but it was shooting off to the right, 8 clicks to the left put things back where they should be. The picatinny rail mount on the Kel-Tec is incorporated with the forearm and it is made of plastic, I think that is where the problem is. The scope will not be removed now. I will have to see if the scope itself, keeps zero. I am impressed with the scope so far.