Drue either way, you can hunt waterfowl with it.
If this weapon has the invector choke system, you can use steel shot just don't use any choke tighter than Modified.
If it does not have the invector system, you can shoot Bismusth, Kent Tungsten Matrix or Hevi Shot Classic Doubles in 2-3/4" and get the same performance as 3.5" steel or better performance than 3" steel. I have personally experienced these results.