I have a Sako A7, but in 7MM RM.
I topped it with a Burris Signature Select 4X-16X 44MM Ballistic Plex W/ Illuminated Reticle.
Love the set-up, shoots great - no problems !
I recommend getting an objective smaller than 50MM, so that you can mount it on "lower" rings to obtain a good check weld; this is especially important with a magnum rifle. IMO