Mr. Campo,
It was Swett's Battery and command devolved to LT Shannon a member of that battery. Then Calvert's Battery commanded by LT Key was moved into position. I will have to find out later today what type of guns they had.
Respectfully,
Gerald D. Hodge, Jr.
War Between the States Historian
Historian: 39th Georgia Volunteer Infantry Regiment
http://39thgavolinfrgt.homestead.com/39thHomepage.html