Begg to Differ..
Everyone says Kent FASTSTEEL is useless, but I have found the most luck with their 1550 or 1560 loads, #4's, even for the big mallards and pintails (in California at least)
Tried the hevi-steel, tried the blackcloud...I think that velocity trumps what the actual pellet is made out of. Yah sometimes you will send a bird flying if you start to push 40+ yards, but if your using a full choke, you will have good kill power out of 45 easy.