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Home > Small Arms Ammunition > Primer Manufacture > Testing

After spinning, the cases are placed in low-temperature ovens to eliminate the moisture. Before moving to the load line, the cases are tested for primer sensitivity. A sample of dried cases from each lot is selected.  The cases are placed in a test machine with a vertical cartridge chamber beneath a steel ball of known weight. The ball is dropped on the cases from a series of heights. At each height setting, the operator notes the percentage of cases that fire. As the height increases, the energy applied to the case becomes greater, increasing the number of fired cases. Eventually, the height reaches a point where all cases fire.

By applying standard statistical procedures to the data matrix of fired cases and corresponding heights, a value is generated that can be compared to published specifications for primer sensitivity. If that value falls within specifications, the cases are released for loading.

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