Some of the 50's Yugo is pretty good but some will have a pretty high failure to fire rate.
I heard the same thing, unfortunately after I had laid in a good supply of this stuff. Rats. Guys were complaining of hard primers. Much of the failure rate may have been folks shooting the stuff in M48 rifles that still had lots of cosmoline in the bolts, greatly slowing down the strikers.
I throughly cleaned both of my M48s before firing, and have had no failures to fire in either, or the 98k that I tried this stuff in. Maybe I just got some ammo from lots that had been better stored than others. Don't know, but I've been happy with it.
The ammo that I've bought from J&G sales (they're out of it now) is clean and bright, and the boxes look new. Inspection of several cases after firing shows no tendancy to split, and no internal corrosion. Performance of this amo has been excellent. Of course, it's what the M48 was designed for, so the factory targeting of both rifles is spot on, shooting a few inches high at most ranges, as intended.
Everyone here has a good appreciation of the basic Mauser 98 design, so you might seriously consider acquiring a nice Yugo M48, if you haven't done so already. Al matching examples abound. These were dirt cheap a few years back, but the prices have begun to creep up. These are fine rifles. No junk has ever come out of Zestava.
Mitchell's Mausers (widely flogged on internet forums) imported lots of M48s. Fortunately, all Mitchell's did to most was to polish the bolts and butt plates, which came bright from the arsenal anyway. Little harm was done, and these can be really nice rifles.