I use a Garrett Max. The average depth was between 6 & 8 inches for these bullets. It all depends on the hardness of the ground on which they fell. The fact that most known Civil War sites have been dug out for the past 40 years I tend to look for small outskirt camps and trails leading to and from the sites. They always camped on hills especially near springs and streams. I have always believed that the battles did not end on the main battle field. When troops scattered they were chased so metal detecting the surrounding area of a known battle field does make sense.