8x60R is the smokeless version Kropachek bolt action rifle round.
That replaced the 8x56R Kropachek BP round,,which was also used in the Guedes single shot rifle. All for Portugal, Steyr made rifles.

The 8x56R Kropachek case is not the same round as the 8x56R Austrian MAnnlicher.
The Kropechek rounds (8x56/60R) use a case that is larger dia at the base,,like the Lebel round.

Maybe the bbl came from a sporter of some sort made up in the 8x60R Krop round. Then recycled here. It would have had to be set back a bit for rechamber to the 8x50R Austrian Mannlicher rd to remove the oversized rear chamber segment.

Does this sporter still use the M95 en-bloc clips for loading and feeding,,or has the magazine been converted to hold and feed cartridges w/an interupter and feed rail?

Interested to hear what the chamber & bore cast reveal.

Nice sporter. I had a couple 1/2stocked in 8x50R and they were very nice rifles. I made cases from 7.62 Russian at the time.