I just can't see how you can improve on the fork type gauges used in the horizontal position. I can check the entire barrel set in just a couple of minutes, including chamber wall measurements. The measurements are repeatable and I get within 1/1000ths of what Kirk Merrington gives me on barrels I have sent to him. It is light enough and small enough to carry around gun shows.

I have a "Truth Tool" made by Johnathan Pool. It is about $200. It is made to use in the horizontal position.
Here is the gauge:



Zero the gauge by hanging the end of it in the barrels:


Slide the gauge into the barrels while reading the wall thickness:


Edit: I added this picture to try to make it clearer:



Last edited by AmarilloMike; 02/21/12 11:43 AM.

I am glad to be here.