Well, I've now verified (David hasn't concurred yet) that Chairgun mildot calibration is wrong, and also how to work around the problem.

First of all, if you calibrate the scope at 10x magnification, Chairgun will be correct. I suspect most people do calibrate at 10x, and therefore the problem hasn't surfaced before.

The other way to get around the problem (which is needed to calibrate at any other mag than 10x), is to calculate the "DotSep"-value manually, and then enter this value in the Chairgun settings file with a regular text editor (like Notepad). If anyone wants it, I can elaborate on the details, but I suspect that David will fix the built-in calibration in Chairgun, and in the meantime, just calibrate at 10x and you'll be fine.

Regards
-Øyvind