Delta McKenzie Bighorn Sheep 3D Archery Target Replacement Core - Bighorn Sheep 3D Archery Target Replacement Core One of the best things about the Bighorn Sheep 3D Archery Target is that it has replacement parts available. As the core is where the scoring and vital rings are located, it is generally the first part of the target that needs to be replaced. Refresh the core with a Bighorn Sheep 3D Archery Target Replacement Core. Made from E-Z Flex Foam, the core can be easily removed from the target body, and a new core can be slid right into place to extend the life of the target.