You can kill ducks with that load out to 50 -55 yards but you are risking just crippling ducks you will never find. Rule of thumb in timber is tree top high (approx. 35 yards or lower.) Best bet is let 'em get down below tree top and you want have to guess. You also may want to check out your pattern shooting steel shot with a full choke. I shoot basically the same load but with an improved cylinder choke. Test your pattern at 40 yards and you will find out what works best in your gun. Shooting ducks much above tree top will get you labeled as a sky buster pretty quick in most places. As expensive as shells are today and some WMA have a 15 shell limit, long range shooting is a no no. Good luck on your hunting.:thumb: