There has been considerable controversy over the identification of this shell. Recovered from the Battle of Second Manassas (Bull Run), it was originally identified as a 2.9-inch Burton. Research in later years has led some experts to believe it is in fact a 3-inch Dyer shell. At this time it appears that a final verdict is still not in, so until we can say with certainty that it is one or the other, we are referring to it as a "Burton/Dyer" and will let you decide.