I bought a couple of big cases of the newer Czech light ball ammo. It was loaded VERY hot, and I had a lot of case ruptures with it in a couple of rifles. I ended up buyin an rcbs bullet puller and reseating die. I now take the Czech 7.62x54 surplus ammo apart, remove 5% of the load (down to about 45-46 grains of powder) and reseat the bullets. It makes a fantatic load, is highly accurate, and a lot easier on the shoulder. I've gone down as low as 40 grains of powder, making a round with about the same velocity as the 7.62x39, and it makes a great plinking round. (By the way, you need to read up on this yourself if you actually try this, I'm not recommending anyone follow my advice)
I've never had other brands cause these problems. I've had good luck with Hungarian, Rusian, and Bulgarian. Even the old Czech light ball in the blue boxes was good ammo, although it and the older wolf ammo were some of the worst to cause sticky bolt syndrome in my rifles.
Some of the most accurate I've ever shot was brass cased yellow tipped HEAVY ball that I bought many years ago. I've shot it all up and can't remember the country of origin though.
Thats my 2cents.