And one last one, which again distinguishes cartridge headspace.
http://www.sinclairintl.com/.aspx/li...th-Sizing-Die-
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Cartridge Headspace and Over Sizing
Cartridge headspace can be defined as “how much the cartridge case moves forward and backward in the chamber upon firing when the breech or action is fully closed”. When a chamber is reamed by a manufacturer or gunsmith, there are maximum and minimum dimensions that SAAMI (Sporting Arms and Ammunition Manufacturer’s Institute) specifies for the chamber for a particular cartridge. This dimension determines the fixed headspace of the rifle’s chamber.... Excessive sizing will also allow your brass to chamber easily but will create excessive headspace. This extra headspace will allow the case to have excessive forward and backward movement when it is fired...."