I have a Glock factory mag +2 that is on a g17 mag that I own. After messing with it to try and get it off to clean the mag, I wasn't able to move it at all. Any idea on how to take it off? I tried squeezing and pushing, to no avail. It doesn't have the floorplate hole like the other ones I have. I reads Glock 1967 and +2 on the floorplate itself, if hat helps. Thanks in advance.