In answer to one question, the barrels only mark in any place is .410 3" ....picture attached. no made in USA no marks other than .410 3"
Left chamber measurements .4745,, .4780,, .4730,, .4750,, 4785
Right Chamber measurements .4760,, .4730,, 4790,, 4755,, 4785
I have not used a mic very much, but this might mean that the chamber is a Little elliptical not a perfect circle.
I guess I will send them back for a little adjustment toward the .4811 figure that is the standard. I am sure the customer service at CSMC will be as good as I have had in the past
PDD
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