There is an old saying, "Don't jump before you're bit." You seem to be worrying a lot about something that seems to me unlikely to happen.
Still, there is such a thing as a ball screw, used by the front stuffer folks to remove a ball from a muzzle loader. It attaches to a ram-rod or cleaning rod and sounds like what you would need. Or you can just buy a long lag bolt or 4" screw at the hardware store. Either way, you screw it into the over-powder wad and pull.
I don't see any great danger in using either, but if it is of that much concern, why not buy empty paper/plastic shells and load them so the cost per shell is not as great.
Last edited by James K; June 20, 2010 at 03:32 PM.