A wooden bullet.
A wooden bullet. These are hollow light wooden cylinders fired from a large airgun. The police usually fire them at the ground a few yards in front of the protesters so that they splinter and ricochet onto the protesters’ legs. They can sting like hell when they hit unclothed flesh, and cause nasty bruises and cuts when fired directly at people. Rubber bullets were also used — these are much the same size, made of hollow-cored foam rubber.