I have located the training manual for the AC-47. Sandwiching a standard C-47 flight manual are sections on the program, missions, flares, etc. The last section is titled "AC-47 Side Firing Gunnery."
Training Manual- Warning! Large File (11MB)
AC-47 Side Firing Gunnery- Coming Soon (There is some gunnery info in the document above)
All photos Copyright 2007 Chris Smithson
A LOT of people are downloading the training manual, but I never hear from anyone about it. Dop me a line. Maybe it will help motivate me to scan the rest of it. -Chris