S2 also posses another thing that may make your life easy if you want to scope it - Blaser's saddle mount is a neat feature.

Just a personal thought on 500/416 cal - IMO it is a .400 caliber/400 gr bullet with a kick close to .470 NE/500gr. - so I would have hard times to justify one, unless I would intend to shoot over longer distances which I guess I wouldn't. So exclusively for closest distances and nasty things I'd rather pick 470 and for major hunting something with lower recoil like 450/400 or even 9,3x74R - so tough one.