If you take a tripod photo (single vector) of a moving car with a very slow shutter speed and look at the result, you're left with the impression that the moving object (car or shot string on a towed patterning board a la Brister) is "longer" than it really is. The 12 foot long imprint on the moving board is an artifact of a combination of lateral travel of the board and variations in arrival time among the different pellets. So you get what appears to be a "sling effect", even though all of the pellets are exiting the rt. barrel of the 1892 H & H along essentially the same vector because of the fantastically small elapsed time interval?