I would stay away from a bunch of American supplies. Namely Independence, Georgia Arms (reloads), CCI Blazer (aluminum), and RBDC. These companies are the only ones I've ever had problems with, mostly QC, like ammo that is too long OAL, ammo that is under powered, or in the case of Blazer aluminum, it doesn't hold crimps well, so bullets get pulled forward and will lock up a revolver.
I have shot many, many, thousands of rounds of Wolf, Prvi Partizan (PPU), IMI, Aguila, Sellier and Bellot, Fiocchi, Magtech, and even Norinco made ammo. Of all of those the Magtechs sometimes have hard primers, and won't touch off on the first shot, so I tend to avoid them. In particular, I've fired probably 5000 rounds of PPU 158-grain SJFP in .38 Special, never once have I had a problem with it. Quality stuff, love it and shoot it regularly.
-Rob