ricky5042- Since a pic is worth a thousand words, here's how the Hornady/Stoney Point case guage works:
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Fired case, primer removed
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Same case f.l. sized with shoulder pushed back .001 (one thou.)
The ability (and tools required) to properly determine how far the shoulder is being pushed back when the case is resized is the first thing any handloader should have a handle on.
Good shootin'. -Al

Fired case, primer removed

Same case f.l. sized with shoulder pushed back .001 (one thou.)
The ability (and tools required) to properly determine how far the shoulder is being pushed back when the case is resized is the first thing any handloader should have a handle on.
Good shootin'. -Al