RE: Gun shy dog...
unfortunately gun shyness is very hard to cure. Its easier to prevent than to correct...
You have to make the presence of a gun a FUN thing, lay out a gun, walk her into the room with lots of praise, little treats, keep her attention on you. FUN FUN FUN!! Touch the gun a little bit, keep her attention on praise and stuff, have her do some little tricks if she knows any. Simple commands and rewards, while your near or touching the gun. Its a very gradual process, eventually try picking up and carrying the gun while your walking with her, praise praise praise. Start with a cap gun and use praise in the same way as before, making the sound no big deal, not even to pay attention to it. Eventually she may come around.
Good luck.