I recently bought a MS250 and it is a great little saw . And a ell of a lot tougher than you think. And I just rechecked the specs on the MS261. A new one runs a Stihl 26 series Saw Chain which is .325 pitch . And the differance between the new pro and home and ranch saws is the pro models run a rim sprocket system. And have electronic fuel management. Along with alloy crank and tank covers. The larger farm&ranch models have adjustable oilers.