I have the same set up in a 24" barrel. The only thing I have used in it so far was a 1 3/8 oz load of hevi shot #5's hand loaded. Set it up for my nephew when he was 9. After he took his first shot / first bird with it, it has been in my cabinet ever since. That load worked great out to 40. I am not to sure about anything else as far as turkey loads. Wish I could be of more help but I just haven't put any more time into it because I want it to stay the way it is for when I hand it over to him some day.