There were lots of 3” lead loads produced before the mandate of non toxic shot for waterfowl or other hunting. I don’t see anything here that says this is a steel shot tolerant shotgun. I’d guess quite the opposite, the makers had no idea people would be using steel shot, as I’m thinking it is way older than the late 1970s, when steel shot became a thing.
That said, steel has come a ways since it was first stuffed down our throats, and into our guns. If you are talking a steady diet of steel loads, especially 3” versions, that gun will soon change your mind on that, as noted already. Sneaking an upland load in, here and there would likely be OK.
Good luck. I don’t feed steel to any double guns I own that I care about.
Best,
Ted
