Make sure the lever is in "lose" position, that the release is pushed in, and tap rearward on the mount there at the rail with a rubber mallet.Good information Joe, Thanks!
Another question. I have another one that is also a repro. It came attached to a very nice rifle. However when I unlock it I can't get it to come off the rail. It just doesn't move and I'd like to take it off. Any suggestions on how to remove it without damaging something?