I was a AAA/27 shooter and always shot best with a lower rib. My consistently best scores were shot with a Krieghoff Model 32 Vandalia Rib combo but I now use a Beretta 687 Silver Pigeon II unsingle combo primarily because it will be my son's some day and he already has a top single combo.
A lot of people cannot shoot as consistently well with a higher rib and I'm one of them. On overcast days, it is easier for our brain to align the larger muzzle with the target instead of the bead and with a higher rib, that leads to shooting over targets. With a lower rib, the "aiming" error is much less and targets will still break.
My POI tends to be very high - in fact, when I shoot at a patterning board, the lowest pellets are about five inches above the aiming point yet I can accidentally cover a target with the bead and still break it so there obviously is something I do differently when shooting at moving targets with a moving gun.
Ed
