Pretty easy to spot bulgarian contract rifle. The austro-hungarian one simply have budapest or steyr on top of the receiver. If yours have a crest, its a bulgarian contract gun. Year and location of production should be written on the left side of the receiver. Check on top of the chamber for a stamped S or H meaning it got converted to 8x56r. Otherwise it might still be in 8x50r (unlikely, electropencil meant it was arsenal refurb and i doupt it escaped the upgrade)