Okay, I am now out of the arena of what I know. I have an old Stevens 311. As some may know about 20+ years ago I cut the barrel down to 20 inches and used it as my 'bump in the night' gun. Added a sling and stuck a fiber optic front sight on it the first chance I got. Amazing how often the sight of it calmed things down. With my retirement from law enforcement I hunted for years for a full size 28 inch barrel for it. Got one this week. Now I have two barrel sets for the 0ld 311. Problem, the 'new' 28 inch barrel is a very tight fit. With it the gun must be opened over my knee, and some force is required to close it. My goal is to have the new barrel just as sweet to close and open as the old one, without losing the easy opening and easy closing of the old one. How then is the headspace or barrel fit on a double barrel shotgun adjusted?