I have a Winchester 1300. The factory tube that came with it was a .665. I wasn't to happy with it, so I bought a Tru-glo .665 strut stopper. It didn't do much better than the factory tube. I have decided to get a Kick's gobblin thunder and was thinking, maybe the constriction was my problem. I tried several loads in the other tubes but never found one that worked very well. I would like to shoot 3" #5 shot. What constriction have you had good luck with in the Kick's(espically in Winchester 1300's) Thanks, Don