The rifle headspace case gauges assist in proper size die adjustment and in checking cases for whether they need to be trimmed. Essential for long case life, especially with semi-automatic firearms. When setting up your sizer die on a Dillon press ensure that you have brass at all the stations to give you consistent results.
The handgun case gages allow you to check your handgun ammunition to ensure it will fit a minimum sized chamber.
Dillon case gages are constructed of stainless steel for long life.