Thanks for the great photo. That is the same approximate length of the 2-1/2 inch shell's shot-cup that I have, 22.8mm. I was hoping that the cups would be different lengths for simple discrimination. I have three cups, six BB's and seven cylindrical disks. Not enough to equal three 2-1/2 inch shot shells. I doubt that a 3 inch was used, but it cannot be confirmed.