Thanks Gnoman I will try McMaster-Carr, or there is one in Reading, can't think of the name.

As for the dial indicator on the tube, I pick it up and move the block along the tube in increments of usually 3" for readings, and let the stem down on the barrels.

I tried what you said by taking the barrels off the pillars and re-installing them. The reading was within .001 of the previous reading.

In the enclosed picture you can see the overhang of the alumium block with the indicator. The spring loaded needle takes up any movement and does not make the block rise because the weight of block and indicator over ride the spring tension.
That is my theory.

Bad picture of barrels mounted on gage.

David