The 555 PG was a great choke with the older H-13 #6 loads that are not available today.2006 or so production, big turkey on box.
The Truglo SSX and Sumtoy chokes are two chokes that shoot very well with the H-13 and Fed HW loads in my guns . With all the changes in shot size, powder, wads and all it seems to be a crap shoot between the 550, 562, and 570 chokes as the best chokes for a shell. When it gets down to 30 yard and under shots it really doesn't seem to matter in #6 or #7 shot as for killing turkeys.
A 20 gauge from 30 -40 yards is a whole nother animal and you need to decide for yourself.