Within every centerfire primer is a group of subcomponents assembled to exceptionally precise tolerances. Primer cup dimensions are controlled to four decimal places. The priming mix is specially formulated for consistent ignition with a wide variety of powder types, and tested for reliability over a temperature range of -20F to +150F. Individual primer pellet weight is controlled to .01 grams. Specifications and Features: Application: Reloading Boxes Per Case: 5 Caliber: 357 Mag Gun Type: Pistol Material: Universal Quantity: 100 Per Box Recommended Usage: Reloading Series: Centerfire Primer Size: Small Pistol Mag Style: Small Type: Primer