Yeah, that's the way I did it before laser rangefinders and scopes designed for dialing. Used a Duplex reticle as both a rangefinder and longer-range aiming point. Was guiding back then, partly for antelope, and being able to put a wounded one down at what was then considered long range came in handy on occasion. Finished one buck somebody else had wounded at around 550--took two shots to get it done, but was very close on the first one, thanks to having a realistic idea of the range.
