Doing my head in now. How much difference do you see between different chronos? Always used my F1 to set up, and seeing Express 7.9's spitting out at around 810-815 fps. Got a Skan Pro 1 to use indoors if needed, but that is showing around 30fps less. Obviously something going on so I borrowed a Combro hoping that it would confirm one or the other. Combro is showing a few fps less than the F1, but not much (less than 10fps). Would appear that the Skan is not quite right, but how do I pick the bones out of that lot??????