It's a common prob between guns/barrels that are a few years apart. Sometimes it's so pronounced, it's a serrated grinding sort of sound when the action bar collar hits that rough part of the barrel flat. The action tube is the cheapest....general gunsmithing rule #1 is always modify the cheapest part. If it goes wrong, it's cheaper to replace. The flat on the barrel can be stoned down smooth, too, if necessary. It's not going to affect anything except the bluing on both parts and a bottle of cold bluing will fix that. Stone both if you want. It's like a paper's thickness.
It's the action bar collar, John, rubbing on the barrel flat. It's exactly what you're thinking.