You attack harmless milk jugs and pumpkins?
Well, I was trying to harvest the pumpkins for Thanksgiving, but unfortunately for me, the 6.5x55 left me with no edible meat!
But let me ask you this: How am I supposed to catch a pumpkin without shooting it first?
As for the milk jugs, well, those were communist milk jugs. After I'm done drinking the milk, I fill the empty jugs with water (some add red food coloring to aid in target ID and for spectacular effect) and take them out for practice. With a high velocity round, the jugs simply explode when the bullet passes thru since water cannot be compressed; it has to go somewhere. Then when I am done, I make sure to clean up my mess before I leave. However, since a pumpkin is biodegradable, I just leave those out there as a warning to the rest.
Now, with regards to shooting the kitty litter container, it might be possible that you shot too high and hit the wire. But, I've noticed that even when shooting an empty container, you can knock it around a lot and "make it dance." So it's quite possible that you hit the container so hard that the wire either snapped, became loosened, or even cut thru the plastic. If I were to try to rig something like that, I'd use two metal chains.