Pin Gages - How to Read Them

[John Boy]

http://www.aajansson.com/pdf/understanding-fixed-limit-gages.pdf

[The Original Lumpy Gritz]

And don't ever drop a pin-gauge. 

OLG

[Trailrider #896]

Something similar with headspace gages.  There are generally three gages in a set: GO, NO-GO and sometimes FIELD.  When checking headspace on a rifle, the extractor and ejector should normally NOT be in the gun so as to preclude false readings.  The chamber should allow the gun to be closed WITHOUT FORCE.  While one would normally assume that the gun should NOT CLOSE on the NO-GO gage, this gage is actually to be used by a gunsmith when setting up the headspace during chambering with the reamer.  Most of us would prefer that the gun not accept the NO-GO gage, as it gives us a little safety in case of wear and tear.  A gun should definitely NOT accept a NO-GO gage!  Now, you can burn up the wires telling me why a gun should never accept a NO-GO gage.

[Ron "Ironhead" Smith]

1 hour ago, Trailrider #896 said:

Something similar with headspace gages.  There are generally three gages in a set: GO, NO-GO and sometimes FIELD.  When checking headspace on a rifle, the extractor and ejector should normally NOT be in the gun so as to preclude false readings.  The chamber should allow the gun to be closed WITHOUT FORCE.  While one would normally assume that the gun should NOT CLOSE on the NO-GO gage, this gage is actually to be used by a gunsmith when setting up the headspace during chambering with the reamer.  Most of us would prefer that the gun not accept the NO-GO gage, as it gives us a little safety in case of wear and tear.  A gun should definitely NOT accept a NO-GO gage!  Now, you can burn up the wires telling me why a gun should never accept a NO-GO gage.

The headspace gages I own for rimless cartridges get modified to this configuration. Extractor and ejector can stay in place.

[Ramblin Gambler]

I thought the extractor just had to come out to prevent damage to the gauge.  So when I used mine, I carefully put it under the extractor.  I might have gotten a bad reading doing that?