Pete,
The comment earlier was that they were"reamed". Did that mean someone with a 2 3/4 reamer or a forcing cone reamer took the barrel chambers out?
I do not recall if the chambers were lengthened. I know that RMC confirmed from the photos that some one had been in there. I seem to recall that when he measured the wall thickness, it was on the thin side.
You can see the tool marks in these photos.
The damascus fragmented, which is what it should have done.
I can not emphasis enough about how important it is to measure a gun before firing. Some time back, I purchased a German sxs with very nice Bernard damascus barrels, that was made circa 1870. I measured the chambers and found them very thin. Upon close inspection with a bore light I could make out faint tool marks. Needless to say, it is not a shooter. I did keep it, because I wanted a gun with Bernard damascus.
Pete