Buster, thanks for the suggestion--I snugged it up as tight as I dared, but will re-check it. I did notice that the barrel band seem to be in a different place on the tube when the top set screw is aligned with the indentation in the barrel--I guess that makes sense due to the longer length of the breech.
Anyway, I'll tear it down this weekend and see if I can see any defects in the breech.
