I use a modified for dove and quail and 6 shot - those euros are tough!

Use a full for goose and duck. Sometimes a modified for duck if we are jumping canals.

Use a full for turkey.

My boy downed his first turkey with a modified last year.

Please do what the posters above have said about getting it looked at. If you are shooting without the choke in, those threads will grab gunk and turn it into a time bomb for you.