I am looking for a "Low Tech" range finding tool of some sort, to add to my range box. I want a tool that actually works well, and not just a cool gadget showpiece. I recently saw an adjustable brass "Primitive Range Finder, patterned from an antique circa 1869" on TOTW made by TDC. I am looking for something very simple like this, but need not be "period correct" as long as it does the job. Would this be a good tool for ranging my Flinters? Or are these just gimmicky? What do you folks use and/or what would you suggest? Any tips on using these instruments or just any opinions you may have in general on this subject is welcome. Joel