As topgun so reasonably put it, It's not the gun but the choke tube. It's obviously not the gun itself since it shoots fine with other tubes threaded in. Sometimes you get one that shoots "off" because of a very slight "canting" on the threads and this shows up more so on extra full chokes. It could very well be that the threading on the choke tube is off. Never had use for those "extra full" jobs anyway. Always gotten by very well with a full. Actually killed quite a few Turkeys with Modified. All extra full does for me is increase recoil.