Pete; I am a little fuzzy on it's history, but believe it was developed by a Mr Rutledge. Seems he was a designer for either Winchester or Remington, not sure which, maybe neither. I do recall reading about them from years past. Should be someone here with the details on this, Help!! I think that maybe Mossberg had a hand in the Mo-Skeet-O game, but didn't develope the Rutledge Bore.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra