Lyman Ammo Checkers verify the quality and consistency of both reloaded and factory ammunition. They are machined from solid aluminum and cut with custom tooling to SAAMI minimum chamber tolerances. Just drop your cartridge into the gauge and if it fits, it will chamber in your gun. Each gauge is clearly marked for caliber and is anodized in a bright orange color so they will be easy to spot on your reloading bench. Specifications: - Caliber: .458 Socom - Material: Aluminum