Hurray, Aquillion is teh winnar. It's not as though abusing it would end up being a serious tactic...
Honesly I would make it hard to get ammo box killed with general explosions. Give the ammo box 100 health. The damage resistance would be something like this. .15 to bullets .05 to explosions Getting run over or decon would be normal damage so the amount of 100 health has to be low to decon it fast.
not really related, but thats 15% or 15‰? assuming its being percent - will it be 15% damage or 15% less (=85%) damage? idk it all sounds kinda resonable to me