I have a Tasco Tactical 10X 42 Mil-Dot, till now I don't know how to use the Mil-Dot rectile, I've only had it for 1 week now. Thats not the issue, the scope it self has a parallex setting 10m -> infinity, I noticed that by just adjusting the parallex I can tell approx. the distance to the target. Where ever the target is, I keep adjusting the parallex till I get a sharp picture with a sharp cross, then when I am sure this is as sharp as it gets I look at the adjustment to see the distance mark, then compare it to the real distance of the target and pretty much 100% of the time I get the distance right. my question is, is that a valid way to tell the distance to the target? Because I find this a more efficient way than a range finder, hence you don't have to leave you rifle for one second. With my scope I can get accurate results up to 500m, after that all it says on the adjustment mark is infinity, but atleast you know its more than 500m.