Used RCBS .45-500 BPS mold blocks, with RCBS handles, nice condition. RCBS Bullet Molds are machined from solid cast iron blocks to exacting specifications to ensure accurate, clean, repeatable castings cast after cast. The blocks are precision ground square prior to machining and steel alignment pins are used to ensure perfect mating of mold blocks even after years of heavy use. All RCBS mold blocks feature a 3/16" thick sold steel sprue plate held tightly in place with tempered steel spring washers and screws.