I have a 630 jonsered that had a 20 inch 3/8chain bar,I had to get a new bar,so I went with an oregon power match 24 inch. The saw guy said I could not use 91 series low pro chain,bull.I bought some 91 chain and put it up against the 3/8 and the drive teeth were exactly the same. It cuts like a tazmanian devil on a cartoon ,I mean it is wicked how much faster it cuts and it don't waste half the wood as the 3/8 chain. I don't ever plan to buy another regular 3/8 chain again. I have run 5 or 6 tanks of gas through it since I put the chain on and I can't see any out of the ordinary wear on the chain or sprocket.