Many times, bullets that are not casting round is due to the mold lacking lubrication.
Aluminum molds require occasional lubrication. They should be re-lubricated if/when you notice the sprue plate begins to become more difficult to move and/or when the mold blocks do not line up when the mold is closed. Lack of lubrication will cause the mold blocks to mis-align, or the sprue plate to gall the top surface of the mold.
A technique that works well is to have a glob of hard, stick-type bullet lube (like beeswax or Permatex Anti-seize) about the size of a .45 slug rolled into a football; when the mold gets hot, touch one end to the aligning grooves along the sides of the mold block, on the underside of the sprue plate, and on the steel pins along the bottom of the mold block. Use sparingly, as if any gets into the mold cavity it will cause wrinkled bullets.
