Yo, I'll try to be descriptive on this but I can use the ballistic weapons and missiles as an example. I figure that although there are only two axes of movement, the third, imaginative axis, is represented by the disappearances of missiles and bullets that exceed their ranges. One would assume that from a long enough distance away from a bullet, the target would have moved only a small degree in any direction to cause that bullet to miss, hence its disappearance into the imaginative third axis.
Wreckage of defeated opponents can also behave this way, floating into the imaginative third axis to no longer block aim.
Does wreckage disappear already? I haven't really noticed but I would prefer they do after a minute or a half-minute as the screen does get clogged sometimes. I find myself hammering round after round like a brute wishing for these things to pop already.