The first time I saw on of these was in the early 80's. One of the old farts at Chanute AFB, who was probably younger then than I am now, was using one on the skeet field. It looked like a Chinese fire drill. Plug fork in to shoot singles, load a shell, shoot, work the hull out and put in a pouch, load another shell, shoot, work the hull out and put in a pouch, take fork out, place fork in pouch, load two shells, shoot doubles, bend down and pick up two shells...
Hap, I think the Remington Rep was blowing smoke. The added weight would slow down the bolt assembly (bolt, action bar, action bar sleeve), much the same way a heavier magnum action bar sleeve are by some shooters used to reduce felt recoil.
Michael