What choke for a Benelli M2

[ahfox16]

My buddy is running a .570 Pure Gold out of his Benelli. Averages at 150 using Nitro 7's at 40 yards.   He didn't want anything tighter then that.  I was running a .555 IC out of my Benelli and averaged about 180 at 40 yards using Nitro 7's.  I've since switched to Federal Heavyweight in size 7 and average about 150, but have switched to a Sumtoy.  The Indian Creek had the wad catchers and didn't pattern the Heavyweights with the flight control wad very well.  I'm happy with the heavyweights with the Sumtoy.  Believe it is a 562.  It's a 45 yard gun easy and that is plenty good enough.