I've noticed that the new jets that I can buy do not always match up physical size wise with older jets of the same marking. At one time I saw a graph (from maybe Myron?) that showed the old bing jets having a different scale than the new ones. It may had something to do with the way the numbers are stamped on the side. ie different font sizes are a different scale. If anyone knows what the deal is or has a copy of the scale chart I'd thank you kindly.