Well not to argue with you, but with the two I have the arbor hole bored in the barrels of both of mine have a concave bottom, not at all square and the flat spacers I tried wanted to cock to one side or another. I did try a series of spacers required to bottom out the arbor in the arbor hole and found that I had too large a barrel/cylinder gap in both revolvers when the arbor was bottemed and square with the frame and I would have to machine the frame to tighten it up to acceptable standards. I think Uberti is aware of this condition and figures it's cheaper to let the customer set the barrel gap with the wedge than to properly fit the arbor to the arbor hole. That is not the way it was designed to work, setting the barrel gap that way tourques the barrel upwards as can be seen by the pie shaped gap when held up to the light. I don't think most of the people buying these guns are aware of this, I know I wasn't. I would be willing to pay more for the revolver if that's what it would take to have it made to work right out of the box the way it was orgionaly designed to do.
Was the arbor hole square and flat in the barrel of your revolver and how did you measure to determine the correct thickness of your spacer? Again I don't mean to sound sour or to argue and I do like the revolvers otherwise but I guess I'm a bit of a perfectionist