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.
Larry isn't tungsten denser than lead? I hunted with both bismuth (the old Pederson Bismuth Cartridge Company) and tungsten matrix (Kent) shells for waterfowl and found that the tungsten matrix is head and shoulders over the bismuth. Of course it could be the velocity difference between these shells also.
