So steel is a compromise. It isn't as heavy as lead. It doesn't carry as far. It loses its energy more quickly. A generation of waterfowlers suddenly had to change habits and instincts that were formed on the basis of a lifetime of lead shot.
Shotgun performance is measured by the pattern of the shot fired by the gun.
A full choke gun will deliver about 70 percent of the lead shot into a 30-inch circle at 40 yards. Or look at it another way. Half of the pellets spread over that 30-inch circle should bag a bird. A general rule for lead shot is that a full choke gun will give that performance out to 50 yards. And that's how hunters made the shooting decision.