I have a Carlson .675 Tube on my 835 and it paterns very well,the only problem is that it is ported,so I can't use the new Federal Ammo with the Flight Control Wad(the porting pulls the wad off of the shot column like a standard wad),Therfore whatever choke tube you decide on,also consider if you want to shoot Federal Ammo and if you want it ported.

Bill