There's no PPU submachine gun ammo. Furthermore, Yugoslavia nor Serbia used any 9x18 Makarov. It's possible they had access to them but neither the gun nor the caliber was ever a general issue. The military and police used the 7.62 Tokarev up until 1992. The submachine guns they used were Yugoslav variants of the Russian PPS and PPSH, both chambered in 7.62x25 Tokarev.

Sent from my XT1650 using Tapatalk