David,
You will find in Military Annals of Tennessee, Confederate, Edited by John Berrien Lindsley, Broadfoot Publishing Co., Wilmington, NC, V2, p. 873, a casualty list for the "Lookout Artillery, Capt. Robert L. Barry." This document is also known as Lindsley's Annals.
Five men are listed: Ford, Thomas J., d. Nov.9, 1862; Roberts, F. M., d. Sept. 16, 1863, in hospital at Newton, Miss.; Maurice, M., d. at Pollard, March 6, 1863; Underwood, E. R., d. Sept. 14, 1863, in hospital at Lauderdale Springs, Miss.; & Carson, W. A., d. in hospital at Greenville, Ala., June 19, 1863.
Incidentially, Tennesseans in the Civil War, Part 2 show two John Cooks; a John B., and a John M. Cook in the battery.
Good Hunting,
George Martin