Shotgun bead=front sight. (Some have an extra one in the middle.)

I'm not conscious of how much rib I see when I shoot birds; try not to be when I shoot targets (mostly skeet). But when I'm evaluating a potential shotgun purchase for fit, if I mount the gun like I would when hunting (don't try to "sight" down the barrels) and can't see either rib or bead, I know the stock has too much drop.