NEW Primed .357 Magnum Pistol Brass Cases New Brass Case Primed Cases Ready for Loading 500 Casings Save time on prep work with new .357 Magnum primed brass cases. Each case features a clean, uniform primer pocket and durable brass construction, making them suitable for multiple reloads. Primed with a Ginex small pistol reloading primer, these .357 mag brass cases streamline the loading process and get you shooting sooner.