So I stumbled across an old gun at a local pawn shop (I rarely shop pawn places, but this is the only one in the area with a gun counter).
The ornate trigger guard and fat bolt shroud immediately suggested a "Vetterli" - but my knowledge stopped at the name.
Surprisingly, the tag said "6.5mm" for the caliber. I think they wanted about $100 for it - which was also a surprise because this shop's prices tend to be sky high. What was I looking at?
My weak Google-fu turned up this strange tale:
http://candrsenal.com/rifle-italian-vetterli-carcano-m708715/
It's a good read.
For the TL;DR crowd: this Vetterli started as a single shot black powder gun in 1870. Then in 1887, they bolted on a magazine system. Then, desperate for guns during WWI, they soldered in a rifled barrel liner in 6.5 Carcano and started shooting smokeless loads out of these. Then for WW2, they shipped them off to Italy's African colonies.
As interesting as the gun's history is, I just don't want one - not even for $100. I'll shoot most any old gun in good condition. But this cobbled-together version of a gun introduced just after our U.S. Civil war is just too much - even for me.
If anyone in the DC area is desperate to own it, shoot me a PM & you can go see if it's still there (hope that's OK with the moderator; if not, I'll happily remove it. And no, this isn't my gun and never was nor will it ever be).
Enjoy