While browsing http://naboje.org i discovered a 5.45x39 cartridge from plant #21 indentified as Hungarian as the year “88” is not inversed.
Apart from the common mistake that #21 is not Sirok but Veszprém, as far as i know Hungary never produced this caliber. The lacquer finish also doesn’t look Hungarian.
Examining the details of the fonts it uses a quite unique “2” that lower part is half the width of the font itself. I found the same “2” on Polish 7,62x39 cartridges. See picture below from the same site. So i would identify this as Zaktady Matalowe MESKO SA of Poland.
My question is: Is the year not inversed by error, or is it a covert production lot for export?