is it rough opening or closing? Or both? My Cooey 12ga is pretty stiff, even after probably 1000's of rounds. The main thing for me is on closing, the extractor slides against the breech face to push it back in. It's worn a good sized groove in the breech face, I think I will try to round off and polish the extractor so as to be a little easier on it. Other than that, a good cleaning, a bit of polishing/lapping, and good lubes ( I like Militec, get the free sample) will go a long way.
Drew