Now with a trap gun, most guys liked to have their beads stacked because you are shooting at rising targets almost all of the time. So you will then see the entire rib, in most cases. (But the rib on a trap gun can still taper downward (as it gets toward the muzzle)on top of the barrel. You can still stack your beads because the buttstock is made so that you face is lifted up over the gun and you are looking down on the rib. This is why people have adjustable cheek pieces, so they can adjust them to fit their faces. Trap guns shoot 70/30, 65/35, etc. meaning that 70% of the shot will be above where they are aiming and 30% is below. I can't imagine hunting with a field gun with the rib in a position where you see the whole rib on a falling bird. But I think the answer to this question is: It depends on the target and what type of gun you are using and what type of sight picture you need to have.
