well a case came apart, but others at the same charge and higher did not and they were all below max charge. I suspect a bad case from past reloading.
as for the groups, I'm going to load some more and try them without the break. one load had three shots overlapping each other, the others were about 1 - 2 inches.
a local "expert" in town built it and put it on. I'll call him tomorrow and see what he has to say.

John, your boss id is .340? I would expect .020 - .040 clearance to allow for any machining errors at the end of the barrel to the id of the barrel and the break thread to bore of the break. I need to get some plug gauges to check the id of the break through the length and to the id of the barrel.