My practice method is to use an 8.5x11" sheet of black construction paper placed horizontally on my target frame. I shoot prone, sitting, kneeling and offhand as well as using whatever makeshift rests I can find at distances out to 300 yards.
The paper fairly closely approximates a kill zone and lets me know where my limit is on range and position and where I need to practice. I can keep my shots on the paper at 300 in every position but offhand. My limit offhand is 225 yards. Beyond that I start to have one off paper occasionally.
