First of all, give us some info. Are you using a pot or ladle pouring. Make sure the mold is hot. I don't know where you live, but if it is cold outside, you need to get inside, as the lead will cool before it has a chance to fill the mold cavity. Pot may not be hot enough and/or won't stay hot because it is too cold outside. A lot of possibilities here, need to supply us with more info. This way we can hopefully pinpoint your problem.