Cartridge I.D. ......
MC600.....got a tough one there. Looks like a three (3) element head stamp and marked with the cal.,which is usually not done for military ammo. The '79' is reminicent of a Soviet/Russian or Chinese factory code. The stars are also typical of eastern european markings and the cal. marking is strictly for a commerical cartridge. My guess,w/o seeing the bullet type or construction,is that it is not a Nato country,is not for military use and is most likely is from Bulgaria or Romania. At first it resembled South African....remember they had sanctions and did not want anyone to know where their ammo was made. It could also be from another African country. IMO,therefore....and my best guess is Romanian.....good luck with further I.D......might get someone with the same ammo in the packaging. Then it could be nailed down conclusively.