The sunlight filters through the trees as your target moves within sight. You dope the range at just over 650 yards, an easy shot on a flat range. But the target lies downhill at a slope of over 30 degrees! You know you need to hold low, but how low? When every second counts, you can't afford to make a mistake.
The Slope Doper is a handy tool that will allow you to optically determine the slope, and read off the conversion factor. Dial... trigger pull... hit!