Have been using bismuth shot, both in factory and handloads, since 1996 in gauges from 28 to 10. It kills waterfowl just as well as lead shot (if anybody else here is old enough to remember those days), even though bismuth shot a little lighter in the same sizes, around 90% of lead, because there are 10% more shot in the same charge.
It also generally patterns much like lead shot in the same chokes, though some of that depends on the wads used in the ammo. Practicing before hunting with lead-shot equivalent loads helps a lot, and costs less.
Bought a case of Kent 2-3/4" bismuth ammo loaded with an ounce of #5s a couple-three years ago (2-3/4" because many of our 20s have that chamber) and it has worked very well on both ducks and pheasants.
