Jere,
The James River Publications site at:

http://www.mosocco.com/georgia.html

contains this informarion that may be useful:
"40th Georgia Infantry" ...was organized during the fall of 1861 and raised its companies in Bartow, Calhoun, Gordon, Whitfield, Paulding, and Haralson counties. It moved to Tennessee, then Mississippi, and was placed in Barton's Brigade, Department of Mississippi and East Louisiana. The 40th participated in the conflicts at Chickaswaw Bayou and Champion's Hill and was part of the garrison surrendered at Vicksburg on July 4, 1863. After being exchanged it was attached to General Stovall's Brigade, Army of Tennessee, served on many battlefields from Chattanooga to Nashville, and ended the war in North Carolina. The regiment reported 36 casualties at Chattanooga, totalled 223 men and 105 arms in December, 1863, and had 74 effectives in November, 1864. It surrendered on April 26, 1865. The field officers were Colonel Abda Johnson, Lieutenant Colonel Robert M. Young, and Major Raleigh S. Camp." For more info. go to: US Army Website you'll find a bibliography of publications relating to the the 40th GA. Infantry. If there are any items listed there of interest to you, you can get copies by writing to the U.S. Army Military History Institute, ATTN: Historical Reference Branch, 22 Ashburn Drive, Carlisle Barracks, Carlisle, PA 17013-5008. Their charges are $10.00 for the first ten pages of copying and $.25 for each additional page up to 300 pages per year per patron. Checks should be made payable to the Defense Accounting Officer, but mailed to the above address. (again thanks to Brian Heintzelman Salado, Texas (CochiseH@aol.com)"

There is also a website on the 40th Georgia Infantry at:

http://www.nwinfo.net/~jagriffin/40th.htm

You may also, since you have his name and regiment, submit it to either the National Archives in Wash.D.C., or the Georgia Dept. of Archives and History in Atlanta. They should have his CSA compiled service record, that may or may not list where/how he was killed. This should get you started.....good luck. I hope you find him.......