Great advice from Greg and Kurt.

While I've had some excellent custom big dollar .45-70 molds, most of the centerfire cartridge molds I use these days are from NOE, Accurate, and Arsenal, always aluminum, for .45-70 and .44Magnum alloy casting of bullets and slicks.

Getting the mold really clean and free of any surface contaminants/oils/etc is imperative, as is preheating the mold (I use a hot plate) and starting off with really Hot alloy, and quick flip compression casting with a proper ladle (personally never liked those dang pot bottom dribblers).