To drop the back and forth on what we should or shouldn't do re lead vs nontoxic shot: Kent does (or did) offer Tungsten Matrix in low pressure 2 1/2" shells for vintage doubles. I think maybe 12ga only. But I have some. Fortunately, being an upland hunter and not a waterfowler, about the only time I have to use nontox is if I'm hunting pheasants in a wetland area and the entire area is nontox, no matter if you're shooting pheasants and not ducks. If I were hunting a lot of federal Waterfowl Production Areas (which are all nontox only) for pheasants, I'd probably need a lot more than I have.
The good thing about TM from a ballistic standpoint: It's the closest in terms of density to lead, of all the nontox alternatives.
Concerning pressure information, if those Rio bismuth loads are marked as CIP-approved FOR STANDARD PROOF GUNS, then they should be good to go in our vintage doubles.
