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Case Annealing

Annealing is a heat treatment process that changes the physical and sometimes also the chemical properties of a material to increase ductility and reduce the hardness to make it more workable. The annealing process requires the material above its recrystallisation temperature for a set amount of time before cooling. The cooling rate depends upon the types of metals being annealed.

The main reason for annealing rifle brass cartridge casings is to prevent case necks from splitting which they will, eventually, because firing and resizing casings “work hardens” brass, making the thin necks brittle. Most rifle cases will survive four or five firings, and some will last longer, depending on the brand and method of resizing. Many handloaders avoid the issue entirely by retiring brass after several firings.