Core Diameter: .247 - these cores are designed to be used in Corbin's Press and Die Sets [Recommended for .25 Caliber]. Tired of cutting your own cores, or casting cores at your specific grain weight? Let Corbin's help by cutting those cores for your, so you can get back to doing what you love, shooting.Say goodbye to tedious manual cutting and trimming. With our precut cores, you'll spend less time prepping and more time perfecting your projectiles. Get ready to streamline your reloading process and maximize your efficiency. Crafted from Corbin's premium lead material, our precut cores ensure consistency and accuracy in every bullet you produce and are guaranteed to not clog your dies bleed holes. Say goodbye to inconsistencies and hello to tighter groupings and superior performance. These are made to order, and the count is determined by the grain weight listed. If you want to know how many cores you will receive just divide your total ordered weight by the grain weight slug you'll be making. Cores will be delivered within 3 grains of the listed weight.