I recently picked up a second hand Smith enterprises mount for my M1A on the cheap, but the kicker is that the main screw is missing. Does anybody have any advice on how I can go about getting a main screw? I have already emailed SEI and do not have a reply yet. I haven't seen these main screws available anywhere including SEI's webpage. Are the main screws unavailable on their own? If so, then the sweet deal I got suddenly makes me feel foolish.