I don't shoot much waterfowl, but I shoot nothing but steel in ten gauge guns not recommended for steel. The patterns shot out of my unmodified AYA ten are so tight it's hard to believe. Don't drill your chokes out like was recommended thirty five years ago. The fuller the choke the tighter the pattern and the steel shot does not seem to harm the choke area in a gun with a little steel in that area. The Browning Superposed 3" gun is like a Model 12 3" gun. The tubes and muzzles are built heavier than the standard gun. Now, there are factory 3" guns that do not have extra steel in the muzzles, like the Model 21 Duck Gun. Don't shoot steel in a Model 21 Duck or Magnum Grade gun. The tubes are standard thickness. I know of three standard barrel Fox guns that have shot a bit of steel with no adverse effects with no opening of the chokes. Measure your barrels and buy the cheap steel ammo
