Good shotguns, I shoot Federal 3.5 inch in mine. As you said, steel shot isn't a good idea and can result in barrel bulges. I've seen some 711s with cut down barrels, they look like oversize coach guns. You get 18 00 pellets, twice the amount of a 12 gauge 2.75.
Lol it would look like a really oversized coach gun. And is that the federal grand slam? I was wondering if it could handle buck shot or turkey loads alright. It still has its full length barrels which I assume are full choke. 19.5 stamped on the barrels. I would guess converting it to inches that's. 768 or around there.