[death2twinkys]

Undoubtly the vagueness of the supressor laws is done at least halfway on purpose to give LE a little bit more give in these situations. The tire idea seems to make the most sense, but you might consider filling the tires with some kind of fiber like old clothers or somthing like that. Since clothe really is a very good sound suppressor, but you would have to pack it fairly tight I would imagine.
I remember right before I moved out of Montana and didnt give a damn what my neighbors thought (they started hassling me before we even started building our house) me and a few friends would sight in our rifles on my drive way, granted we had a few acres and of course shot in a safe direction but it would have been nice to have one of these since my neighbor came over and tried to convince me that I wasn't at home and threatened to call the home owner I laughed at him.