Without going into a long, dragged out story, a co-worker gave me a Chain for my saw (Stihl ms290 -Farmboss)....I'm running a 20" bar. What is on the saw now is a Stihl 26 RS 81 Rapid Super...specs are .325 - .063....the one that was given to me is an Oregon 20LPX081G....specs are ..325 - .050.....what do you think...will it work ? ~Thanks