Just for informational purposes, I was at a gun show two weekends ago, was looking at a shotgun in the ten thousand dollar range. On measuring the bore, I found that is was .070, yes, seventy thousandths, larger than nominal bore size. Now tell me that I shouldn't zero on a ring gauge before measuring constriction. What good is .030 of constriction on a ten thousand dollar gun if it's been hogged out by seventy thousandths?