You might try this website

http://www.itd.nps.gov/cwss/index.html

I have found reference to a Pvt. John M. Knight of the 27th Va. Infantry. co. A. Also mentioned in Carpenter's Battery of the Virginia Light Artillery. Since these 2 units are the same, Carpenter's Battery was formerly Co. A 27th Va., It is apparent that this is the same individual.