Actually, you need a differnt barrel for each chambering. Two bbls are .17 caliber and two are .22 caliber.

Go over to the sako area at www.RimfireCentral.comas I know there's been discussion on this model there.
I believe a scope manufacturer, Burris maybe, makes a scope especially for this gun with adjustments all figured for each chambering. Very nice package as a complete set-up I think. Kinda price prohibative for many but then again, you are getteing what you pay for and Sako is very nice.