Greg has it pretty much correct. Problem is, in the early sixties there was no concept of the myriad of models that have come along. Actually, the first model 110 was what is now known as the 103 Skinner. I still have one, new in the box, and the box says: "110 Skinner" on it (and I have a Buck packing slip to go with it). The 100 series was simply adapting the model numbers that H.H. Buck had already set in motion in the 50's. When we started with the 300 series, the 305 preceeded the 309 by more than a year, that's the reason it has a lower number but is a smaller knife than the 309. No planning, nobody saw what might happen. Al was not a visionary. He WAS a man faithful to God and it is God alone that brought the increase and multiplied the efforts of a humble and faithful man.