>>As for the Dueling ladder, I am fairly sure I saw it posted in the rules that ammo dumping is allowed only after airborne, implying that you can't do it only while waiting on the runway. So I think it is allowed, but you do it at your own risk.<<
From Sour's flight ladder rules...
"1. Guns may not be fired until after the first merge.
2. The initial merge is considered complete once one plane passes aft of the 3/9 region of the other plane."
Seems dumping ammo off the runway is fireing guns before the merge. Now that might seem like splitting hairs, but so is the the idea of dumping ammo after the plane is off the runway. What would be the point of that rule? To protect airport workers? Obviously it was meant to have NO ammo dumping.