[Nick]

What on Earth does "Balkan" mean? That's too non-descript to be used in conjunction with "collection". Is it Romanian, Serbian, Bulgarian, Albanian, Montenegrin, Greek or Turkish? These countries used the three-line rifle in different periods and acquired them under different circumstances.

For example, Bulgaria bought 50,000 obr. 1891 just before the Balkan War of 1912 and these rifles looked like the one on the picture below. During WWI tens of thousands more obr. 1891 were captured by the Bulgarian troops from the Romanians, Russians and Serbians, but they had the 1910 update.

 

[Nick]

... I didn't realize Bulgaria actually bought M91s. I only knew about the WWI captures. If they bought them in 1912, are you saying the Russians sold them only old stock? They were all pre-1910 style?

Yes, 50,000 rifles in pre-1910 configuration with 50,000,000 round-nosed bullets! No "circle-B" markings that I am aware of - I've seen in person two of these rifles, both Sestroretsk-made.

Here are scans from a few Bulgarian sources on this purchase; when Bulgaria entered WWI in 1915 they still had more than 46,000 obr. 1891 rifles in their inventory and many more were captured afterwords: