This data comes from a pilot experiment by Jauhari et al. They fired a sequence of 10 shots through a set of six paper targets that were equally spaced from 3 ft to 18 ft and recorded the size of the pellet pattern at 18 ft.
data(jauhari2.df)M. Jauhari, S. M. Chatterjee, and P. K. Ghosh. Statistical treatment of pellet dispersion data for estimating range of firing. Journal of Forensic Sciences, 17(1):141-149, 1972.