I found this American Derringer at last Saturday's Gun Show and it was in great shape except for the original front sight having been removed. I shaped and glued a standard Glock front sight to the derringer and it was off to the range for testing.
The lower barrel is dead on at 7 yards with 4 different .38 special loads. The upper barrel shoots 6" high and 1" to the left at the same 7 yard distance.
I put a 1" dot 6" low and 1" right of my intended target for an upper barrel sighting point and I was able to to shoot 1" to 2" groups using both barrels of the derringer.
Mark