It actually started life as a 91/30, not an 1891. Has a round reciever. At some time it was converted into a 91/59 carbine but theres no conclusive evidence to suggest the conversion was done in Bulgaria, it was most likely done in Russiaicon. There may or may not be Bulgarian markings on the stock, one looks something like a pine cone and the other a double circle 10. These are property marks not refurb marks. Reasons to doubt Bulgarian manufacture are
1. none were imported from Bulgaria
2.General lack of Bulgarian makers marks
3.first hand accounts of issue to Russian reserve troop and police units
4.Vietnam bringbacks point more to Russian mfg
5.markings and uniformity point to Russian mfg
6. theres at least one know example of a Finnishicon Tikka 91/30 being converted