" Records dated between 1874 and 1902 indicate that more than 800 cannon had at one time or another, been shipped to Gettysburg by the War Department, About one- half of this number ( both bronze and iron with most being pre- Civil War vintage and/ or damaged were eventually melted down and used for monuments, tablets, and statues. The surplus bronze was used for equestrian statues, including those erected of George Meade, Winfield Hancock, and John Sedgwick.
Source: "Silent Sentinels" by George W. Newton.
A good book by the way.