I can't imagine using that tuning fork gizmo at any gunshow I've been to and expecting an accurate reading... Gonna "hang 'em" at the show?

I don't buy guns that don't come with an inspection period and I don't try to get accurate measurements in hopeless situations. I don't know how to use, and don't need to know as long as I have my Galazan gauge on a sturdy benchtop. For the most part, shotguns come to me.
Thank you very much...

And Daryl, I still don't "get it"?