I was fascinated with these things, and seeing as how I'm 34 years old and was never taught to use a slide rule in school, I went to school online and figured this thing out. Using Microsoft Visio, some HP Photo paper and a razor blade, I now have a DIY range tool. I went one level up and added the hold over scale specific to a .308, which I'll test if the rain ever stops.
Pretty cool.
Pretty cool.