I get brass for my 7.5x55 Swiss by buying it from Grafs (when they have it) or buying PRVI Partizan ammo. Or Wolf "Gold" ammo. All three are the same brass, all made in by PRVI Partizan. Grafs just pays them to put their stamp on the case, and Wolf buys their brass as-is. Long story short, I've done all three, it's all good brass, some has over 20 loadings and is still going.
Since they offer 7.62x54R brass also, I would not hesitate to buy brass when you can, and factory ammo when you can't.