Wut?! product tolerance is off - Warne Vapor 30mm 1 Piece MSR Mount

I purchased this mount Because it was low profile and inexpensive-I had had good experience with rings by this manufacturer. The last reviewer Took issue with the amount to type, it is fairly quick to take this on and off, and totally locks the mount in place, which is great. That said, I am sending this back because after taking the screws out, and following the directions to slide the mount onto the back of the rail, I tried to do so on three different receivers, arrow and Daniel defense, and it simply would not slide onto any of them, I even tried to force it on to one, and it marred the rail but would not go on. I contacted the manufacturer who was kind enough to send me a replacement immediately… Only to have the same problem with the replacement, after being assured that this was not a common problem. Am I missing something? I looked in their catalog and back at this listing, it is shown on an AR in the catalog, and filters out as a product for an AR Picatinny on the optics planet Website... Yet both of the examples of this product that I received, when measured with a caliper, We’re a couple hundreds of an inch smaller than the width of any Picatinny I have- It made me think that the casting needed some milling that did not happen/ Sending them back because they are unusable, unfortunate because it is otherwise a great product.