Just keep a bucket of rocks by your door and carry a backpack with rocks in it.
Make sure it’s a clear backpack, though.
But it better be a clear backpack, so the powers that be can see your assault rock stockpile.
As a boy I learned to use a sling and throw small rocks long distances but I never learned to be accurate enough to kill Goliath with it. Even at my age of 73 I could still sling a rock hard enough to take down a criminal but I don’t know how to develop that accuracy. It is a very lethal weapon at fifty yards if you can hit the target.