Actually, I've taken to firing single shots if I am close to the target and behind him. It improves my gunnery. I tap the trigger, and only one round comes out. Just yesterday I did this to an Me-109 who was floating at slow speed and low gee in front of me, and with a single cannon round his wing came off. I knew that damage models in Aces High II are very weak, but I didn't realize that "blew my wing off with one bullet" was literal. I'm sure I can replicate it easily, if I have a cooperative target who will let me get close (or a green pilot who will unwillingly do the same).