I've had something like that, but not in your case. I was in the AT-AT and I shot a lot of times because the main blasters didn't shoot, so I kept firing and I heard the sound, but no fire. Then the blasters went criss-cross and up when I fired down. Don't worry, these things rarely happen. If it happens more than 4 times in 1 time of game-play, check your disk for fingerprints or scratches.
'Helping all in need of SW advice.'