Dave,

I have been working on a regimental history of the 21st Mississippi Infantry for some years now, and here is what I have on John W. Hunter from his service record: He was 25 when he enlisted in the army, and he transferred to Company E, 21st Mississippi, by exchange with A.J. Moore from the 21st Louisiana Infantry on July 25, 1862. He was wounded in the arm at Gettysburg on July 2, 1863, and he was killed in action at Cold Harbor on June 2, 1864. His occupation listed in his service record was farmer. I hope this helps, and if you have any questions, just let me know as I have a good bit of material on the 21st at Gettysburg.
Jeff