Reason for 10x attack scope in GWX2

[Hitman]

no i do it totaly with the marks on the left. for instance if i set the horizontal on the waterline as if you were going to use the stadimeter. but then i line the mast up with the marks on the left then count down from the top. i count each mark as 20, so if its 10 marks then 20 x the mast heigth divided by the the marks up from the horizontal line gives the range

Yup, that's correct, as it means using the "stadia", where the stadimeter takes its name from

http://en.wikipedia.org/wiki/Stadia_rod#Stadia_rods

http://mysite.du.edu/~jcalvert/astro/stadia.htm

http://www.fao.org/docrep/field/003/E7171E/E7171E03.htm