I too am in the process of putting together a 20 gauge turkey/duck gun, using an A5 Mag Browning and asking questions and reading. I am an annal pattern tester, stemming from trap shooting and hand loading duck loads, both starting many years ago. I do have a previous experience with a 20 gauge turkey gun, a decision made from a sore back and long walks. I started with a old M12 20, that I had sent to Briley to install choke tubes, with the understanding I wanted a turkey gun. Briley did an excellent job, and that gun will deliver excellent 30 yd patterns with premium 2 3/4" shells loaded with plated #6's, but I was never comfortable stretching farther, the pattern deteriorated rapidly with distance. Hunting public lands will sometimes make your needs change, and I was on a quest to have a 40 yd 20 gauge. I purchased a M1 S90 Benelli 20 gauge and started testing. Remember that this was a few years ago, everything has improved, most important the info from the internet. I was finally successful, but it wasn't easy, cheap or especially fun. I tested every 20 gauge 3" "turkey" load on the market at the time, made several people mad returning choke tubes, and was eating ibuprophen like M&M's from my shoulder killing me. I was on my 3rd custom choke tube when I stumbled on to some Winchester XX magnums, lighter payload than the turkey loads and bingo, finally something that I could live with. Like the earlier gentleman said, the premium pheasant loads all shot better out of my Benelli than any of the turkey loads. In the end the only thing I really liked about the Benelli was caring it, very light, but kicked like a young mule and the only thing that I found it useful for was turkey hunting. All of the testing I think took it's toll. You will probably get lucky and buy a great choke tube and some of the HW shells and knock the center out of a 10" circle at 40 yds. My luck is I will be shooting a lot of shells and have an up front understanding with the choke tube supplier. Good luck, and probably wouldn't hurt to have some anti inflammatory drugs on hand.
