I bought a husky288 and it came with a 20" bar. The bar had the same pitch and guage as the sprocket and my chain. When i went to cut the chain jumped the bar. I looked up the oregon number of the bar and found that the bar was for a eight toothed sprocket. The sprocket for the 288 was an 7 tooth. Could this have caused the chain to jump off? I have since bought the correct bar. I am milling with this saw on a logosol setup with a ripping chain and am new at it. Hard telling not knowing why the chain jumped, ruined my first chain. Maybe sprocket is worn so I will invest in another??