I went with a SSX for my Mossberg 500 20ga., going to purchase Hevi-Shot 13, either #6 or #7

Let us know how it shoots in your gun. Like I said I have heard good things about the fed hwt 7s and the heavy 13 7s.

I absolutely refuse to shop there since their Pmag shenanigans.

May be of help to you; inner (red) circle is 3", outer circle is 8".....

Thank you for the pictures....I'm going to try the HeviShot 13, #6 with a SSX choke

I ordered a Swarm .555 choke for my wife's Mossberg 20 gauge earlier this week. Hopefully it will pattern well enough that I will feel good "borrowing" it for most of the season!

I found that going to a Bass Pro shop they have a lot of choke selections there for a variety of shotguns. You will not find the majority of them on their web site.

its to late but the .555 by Pure Gold ...

here is a link to the one I purchased. .550

http://allaboutshooting.com/product_...roducts_id=263

Those Wrights Swarm choke tubes are pure death on the turkeys with Hevi-13's!!!! Thats who Hevi-Shot partnered up with when Stewart set the first world record with and has continued since. I have been going to stewart since the 70's for gun and choke tube work. He also has a shop set up at the World Shooting Complex, AKA..The Grand, and does tons of work down there as well.
If I remember correctly, they had 43 pellets in the 3" circle at 40yds and they have to use over the counter ammo to do these events.