Kimio - except for training new shooters, I can't recall any particular advantage of a single shot BOLT action rifle. My dad had a beautiful old Mauser .22LR single shot match rifle - I suppose its advantage was that the cartridge/bullet was never handled by a feeding mechanism. Presumably this is the advantage Scheutzen guys enjoy.
However, I can tell you about three friends who went elk-hunting and the two who used bolt-action rifles had some frozen-action problems when the weather got too cold, but the fella with the Ruger No.1 falling block single-shot did not. A No. 1 has a super-strong action and I'd put it up against an African double gun in that respect except that it doesn't have the second-shot capability you'd want if hunting dangerous game.