For a rifle that is built to look best & still have a floated barrel, the old dollar bill works pretty well. And I would say loosely, at least you want it to slide along under the barrel easily. You better handle it gently while shooting it, though. Much any side or vertical pressure & it will touch the barrel creating a lot of inconsistency. Most all my rifles are built just to be good shooters & some have around a 1/16 clearance to make sure there is never any chance of contact, plus aid barrel cooling a little, too.
