Beretta used to put out an ultralight O/U with the lower barrel rifled. It put out a very nice wide pattern at close ranges, i.e. under 20 yards. This was for hunting in heavy cover where most shots are taken at very close range.
I can't tell you how the large shot will perform with this barrel but the pattern will be wider than with a skeet choke. At much more than 25 yards there will be huge holes in the pattern.
Chuck Graber