I will be using my Dads old A5-20 mag this year. We unfortunately lost Pop this past week. I know there have been dozens of birds taken with this old gun, ( late 60's or early 70's model) just never used it myself. About 6 years ago Dad had a local gunsmith thread the original 26 in barrel and install a custom turkey choke, I believe it's a colonial non-ported brand. All he ever shot turkey's with were fed 2 3/4 #6 game loads, yea, I know those shells won't kill turkey's, but he sure scared a bunch of em to death, because there are quite a few beards hangin on his old gun rack. My suggestion would be try a couple different loads and pick the one that shoots best, then go enjoy the hunt.