How do you tell if a Garand gas cylinder is out of spec....??

[pastprime]

What is used to measure/gauge the gas cylinders? Is there a way to accurately do this using common workshop tools? And what is the minimum inside diameter before they are out of spec?

Reason I ask is that I recently aquired a few and want to verify that they are serviceable before I offer them for sale.

Edited: found what I needed to know.

Information

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[AKA Hugh Uno]

you can get a .300 win mag or other belted magnum in that family of cartridges. if the case-head end (down near the primer) it goes in easily past the belt, the GC is worn. if it barely goes in, its good.

[Orlando]

US Ordnanace Gas Cylinder Gauge

[Bill Ricca]

Sometime a gas cylinder will wear out of round. I have had several where the gage does not go inside until the rotation begins. One it is inside, the cylinder is gone. There were some dealers that set up a chrome process with a cylinder and a matching op rod years ago, to restore worn out cylinders.

Just a note: They are always designated as "Gage".
Make sure you rotate the gage.