This is kind of true, but I've always thought that less than a fag paper separation means the barrel is likely to come into contact with the stock during the firing cycle, so it's not truly free floating.
Neil, if the fag paper catches it means the gap is a little on the thin side. What's the stock on that rifle?
If it's wood, I'd get some fine sand paper and a piece of wooden dowel slightly thinner than the barrel, and gently ease the channel where the paper catches (you'll need to take the action out of the stock to do it) until you can smoothly pass a fag paper all the way down to