You understand that the caliper measurement when taken at the top and a 3/8" dovetail will measure .500 ,but 3/8" as a decimal is .375" as the dovetail reference size is at the bottom of the dovetail and very very difficult to measure so the top of a known dovetail will measure .500" The 11mm will measure .430" at the top. That is due to how Europe measures dovetails as opposed to North America.
R
Ronnie thanks for explaining it to him. I just used a tape measure to do it, as my digital caliper was dead. I must have had the odd ball action that didn't match the chart, hence why I have a 3/8" DIP rail sitting around.
Kinney's offered to take it back as he claims this has happened to others as well. That is why I don't trust the chart anymore.