Anything 16 ga. Unless you can find steel shot. then only if choke mod. or more open.
No steel in my old doubles. Id recommend against it, if not for the bore, worry about ribs popping their solder joints.
Are you sure? Too bad the gun isn't 20ga or he could use Polywad Greenlite #7s. Why wouldn't one be able to use those 20ga and 28ga loads up to say 35 yards in gun with chokes modified or less?
The cheapest 16ga softer-shot non-tox loads were $12.97 or $12.79 per 10 pack of Kent Bismuth when on sale at Cabela's. Those sale prices probably will not be seen again. That load is pretty strong at 1oz 1300fps.
