Like these other boys, I wouldn't recommend steel shot in a vintage double gun either; at least not one that I cared much about. Back in the mid-90's (the Stone Age), I did my own personal experimenting with shooting steel shot in a vintage double gun; a 1907 A.H. Fox A Grade with Krupp barrels. The bores of this gun were a bit rough, so what the heck; how could I ruin an already ruined set of barrels? So I opened both chokes to Improved Cylinder, lengthened the chambers to 3"; and blasted away. I was actually disappointed afterwards that I found no damage to these barrels outside the pitting that was already there. If not catastrophe I'd expected at the very least to see scarring inside the barrel tubes from a steel shot or two being ground against barrel walls; but nothing happened period. My personal experience aside, I would NEVER shoot steel shot thru a tight choked barrel because steel won't compress as does lead shot, which is why I opened the original chokes of this Fox; and although my experience was that the plastic shot cups in the Federal shells I was using was sufficiently thick to eliminate and shot contact with barrel walls, I was probably fortunate. The bottom line is that the risk of damage to a good set of irreplaceable vintage double gun barrels is far too great to be taking chances; so I encourage you to take the advice of these gentlemen.