I have one, DP - lucked out in finding a load that printed both barrels into a group at 50 yards with slight separation, left, left, and right, right- abotu perfect, in other words. It took about 2 pounds of powder and 3 days of 4hour testing per day to find it.
When I started out, the barrels were crossing about 1 1/5" at 50 yards, and shooting 2" high to low between the barrels. it now shoots to one sight with both barrels, and allows the second sight dovetail to be used for a 140 to 150 yard sight.