I had excellent luck with #4 steel on pheasants 30 years ago, while hunting a small river (really a creek) in central Montana, where it was common to jump both roosters and mallards. There weren't any commonly available non-toxics back then, so steel was it. I mostly used 3" 20-gauge ammo, and it knocked the snot out of both pheasants and ducks--but only out to about 30-35 yards. Beyond that killing power dropped off rapidly. Luckily, due to abundant cover along the winding creek, most shots were within that range.
