Thanks ctopher. The Go gage belongs to the supplier. I checked the calibration tag and all was current.
I believe the truth is this: The fasteners are "pacific rim commodities" and are treated without any real urgency to meet spec. but only to meet low cost goals. We american manufacturers...
I'm qualifying a new source (distributor) for our fasteners. When doing a First Article on some #4 and #6 screws, they failed the "Go" gauge for 2A fit. The distributor says I can expect that because of the "zinc" plating. He says they are 2A before plating. My answer was one of total confusion...