This is a Yugoslavian M59/66 SKS rifle used in the Croatian or Bosnian War. The Serbian cross, formed by impressions from empty cartridge mouths, show its provenance.
Cartridge mouth crosses can be seen on a variety of rifles, from WWII Carcanos to this rifle. This may stem from the rounded style of many Orthodox crosses, versus the round case mouths.
The pin on the sling is actually Bulgarian - it has the Bulgarian lion, and white/green/red of the Bulgarian flag. Whether this shows use by a Bulgarian mercenary is up for question; or it could have come from Bulgarian uniform items. Items such as East German helmets and rifles were imported, so Bulgarian gear (especially considering the common border with Serbia) would be within reason.
Cartridge mouth crosses can be seen on a variety of rifles, from WWII Carcanos to this rifle. This may stem from the rounded style of many Orthodox crosses, versus the round case mouths.
The pin on the sling is actually Bulgarian - it has the Bulgarian lion, and white/green/red of the Bulgarian flag. Whether this shows use by a Bulgarian mercenary is up for question; or it could have come from Bulgarian uniform items. Items such as East German helmets and rifles were imported, so Bulgarian gear (especially considering the common border with Serbia) would be within reason.