I press fire and the little guns fire but the big one's don't. Or, even worse, I press fire and I hear pow pow but I don't see any flash from the guns. No ammo is coming out. Its all duds. Its not even duds or blanks. Its nothing is what it is. Its just a sound effect. Pow Pow. What might cause this? It is off and on for all my sorties after 7:00pm today sunday.