Quite disappointing - Leapers UTG MRO Absolute Co-Witness Riser Mount

I thought Leapers UTG was on the way up, but these mounts are terrible. They look good, but they don't fit on any picatinny rails. They're so tight that the guides won't even set down into the grooves at all. This isn't a simple machining error of a few fractions of a millimeter. This is really poor quality control. I painstakingly took the Dremel to it rather than battle through a long return process, but these are absolutely not functional out of the box. I also have the low-profile version and it suffers from the same problem, which also tells me none of them are made properly. It's not worth the already low price. This is the kind of thing that can easily sink Leapers UTG in the American market at a time when they're trying to make a name for themselves as a higher-quality low-cost manufacturer.