In the colder months I do a serious amount of wing shooting and proberly throw somewhere in the region of 2,500 shells at duck.

Yes, steel shot isn't my first choice, but then if that is what we have to use, buy No 3 or 4 shot, since larger the shot, great the momentum it carries. Buy a shell that has the shot "gift wrapped" to take it down the barrel and have you top barrel opened up to half choke.

You will be amazed how tall a duck you can kill with half choke. When I was younger I would shoot full and full but with the wisdom of age, I now shoot quarter and half. What is even better, I get to impress the younger guns, as I only use a 20 bore. Which also doubles as a great excuse when I miss.

You will find it cheaper to hone out a choke, then add a adjustable choke.