I would go with an SKS. If for no other reasons, then for the faster fire rate and a more compact package. Both are very stout. x39 ammo is lighter, and you can carry a whole bunch of them on a handful of stripper clips. When I think survival rifle, I think of something that is rugged, simple, has a decent capacity, and shoots a medium caliber round fairly accurately. I would not feel undergunned with a mosin, however.
