I have one of those Carcanos made in 8x57. They aren't very common at all.
International Firearms out of Montreal had them for sale for one fall catalogue and they were cheap.
I was lucky enough to pick through a bunch of them and found one that was OK only. The rear sight is the normal fixed type found on Carcano carbines and the stock is made from Beech. Mine is marked Terni and 1944 on the barrel. The receiver has one mark only, a large "S" on the ring. The only mark on the bolt, is an "S" on the top root of the handle and an inspectors mark underneath. The only other marks on the rifle, are the Arabic symbols, painted on the left side of the butt and the matching serial number to the barrel.
The receiver ring has a cut out over the mag well. That is to accomodate the S type bullets that were most common by the time of manufacture. The mag, accepts them, in the clip, with ease.
The stock of the rifle has been well taken care of but is well dented and scratched from handling but not abuse.
This was part of an order that was placed by Austria and filled in mid 1944. The bore on my specimen, is excellent and the rifle actually shoots the milsurp offerings I've put through it very well. I had to modify a 7.5 mmx50 mag to accept 8x57 rounds and it feeds well.
WD Ball, in the Book of Small Arms, makes a short comment on them. He had never seen one and couldn't prove they really existed. He was sure they did because he had talked to several people that had been issued them at the close of the war as last ditch rifles.
IMHO, the rifles are safe to shoot and reliable, as long as they are loaded with the cartridges that they were intended for. Standard military ball 7.92x57. (8x57 Mauser) Most North American makers, load this stuff to around 38,000 psi. Well below standard fodder. Good thing to, these little carbines are real brutes to shoot, even from a standing position. Shooting one from a rest on the bench is downright painfull. I didn't even try to shoot it prone.
The rifles are well finished and well made. The bolts operate smoothly and eject the fired cartridges without any problems.
The Carcano gets a bad rep as being a weak action. PO Ackley and several others, didn't believe this was true and put several of them through their paces. They stood up as well as the 98 actions.
The main reason the Italians loaded them in the light 6.5x50 cartridge was because the cartridge was easier on their troops and the rifles. It was a matter of choice that stood them well. The Carcanos and their operators made a staunch team for close to fifty years. The war time propaganda, didn't do them justice.