Progear [verified] Cracker -

By cracking the neck separately and smoothly, shooters reduce the work-hardening stress on the brass. Instead of the aggressive friction of a standard expander ball, the polished mandrel gently stretches the metal to the desired dimension, extending the life of expensive match brass.

The legitimate use cases for such a tool are narrow and ethically gray. However, they generally fall into three categories: progear cracker