Nope, there's no way to delete your games and reset your rating for bullet, or any other formats.
You can only reset lessons and tactics as far as I remember.
Delete Bullet Games?
Sort:
I don't know, man. As far as I know, there's no way to reset that, but you can still try writing to the staff. Maybe they'll do it for you if you request it personally.
?
The OP's gone. Now we'll never know. 
Hi! Is there a way to delete my games and reset my rating for bullet?