Originally Posted by F. Guffey
I have no infatuation with head space gages, there are only three between .000 and .016”+, there are no chamber length gages on the .000-(negitive) side. I make chamber length gages from .012 shorter than minimum length/full length to .016+, that is 28 different length.
I have no infatuation with gauges either, but I do have them in 0.001" steps from the typical 1.630" "go" to the 1.638" "field" gauge for the 308 family of cartridges that I do more chambering for than almost any other family.
I made a "gauge protrusion" micrometer with a micrometer head.
It is zeroed on a granite plate and then allows you to measure how far a headspace gauge protrudes from the barrels torque shoulder,
This same exact measurement can be achieved by measuring to the bolt face from the receiver front ring and adding the thickness of the lug.
It is a very reliable way to work, and combined with a Ptg micrometer adjustable reamer stop, also a very easy and accurate way to work.
I can reliably work under 0.001" levels of chamber depth precision when chambering a barrel.
I would not trust using the depth feature of a set of 6" dial calipers to be as accurate/repeatable as my setup.