Melt a candle on a tray and as it start to cool and solidify push some 357 or what have you brass down in them neck first. When they dry you have some nice wax bullets already loaded up for the kids to shoot at something. Guy I know made a sort of plunger out of a piece of brass and rod so now makes nice little wax bullets for the kids, with just a bit of propellant and the wax plug hand seated they are quite accurate at 15 yards and fun when the kids shoot at these foil plates hanging form something