YIKES!; Suspect Bulgy!
I thought that that lot of explosive Bulgy had been weeded out of the supply chain a couple of years ago!
The stuff to beware of comes in a pink wrapper - like a couple of your packs seem to be.
Dangerous Bulgarian Surplus Ammo:
The best we can figure is that it was some sort of proof test ammo that got accidentally mixed in with the regular milsurp import.
Although some shooters claim to have gone through hundreds of rounds of it without issue, all too many Czech O Matics were destroyed with it, and it's a miracle that no one (that I know of anyway) was seriously hurt.
If you can get a refund on it, I would try. Just hope that the dealer does not foist it off on some other unsuspecting customer.
If he really wants to avoid a lawsuit, he'd best not!
You might be able to salvage the bullets if you reload, but pulling those little 90 gr. pills can be problematic, depending on what system you use to pull bullets. But I would NOT try to fire the pink wrapper stuff with that 52 (or according to some, 53 as well) head stamp!