i have ghosted THR off and on for a while now and when i saw this thread i just had to register and post my 2 bits.
Without a doubt some of the Bulgarian ammo out there is Bad it may or may not be for the Badly overpressure warning that was posted on those geocitys sites that have disappeared.
i received a small crate of the stuff from century and after i noticed that almost half of the cases my CZ52 were spitting out of the stuff had moderate to severe case splits.
since i have never had a problem with any military surplus ammo before (not even click-bang's) i found it rather odd and started looking at the rest of the ammo closely.
atleast 25% or more of the rounds i ordered had minor to severe Case cracks out of the the box a rare few of the cases were cracked straight from the case mouth to almost half way down the case.
(most were cracked at the stab crimps, a good number from the case mouth)
the 7.62x25 round being a pretty stout round mixed with such brittle old brass and bad things can happen, even the pretty strong action of the CZ52 cant hold up to such extreme use for a long period.
its best to examine each and every case before firing under some good light to filter out the bad ones you can see a image of rounds that i found to be bad and unsafe to fire after a short while of sorting:
never had any problems with "good" ones after that but some still split slightly at the stab crimps.
you get what you pay for sometimes with surplus ammo it seems just be careful, that ammo is still a good buy for the price.
EDIT:
Finally found the example image of some of the bad rounds found:
(Click Thumbnail to view larger image)