So my dad has this really old gun from WW2 that his wild guess was a "chinese mauser" and had no idea what the weird test tube shaped bullets it used were, only that they said TERNI 17 PG2315 on the rim (or at least the round he'd picked up to look at did). I did some digging and figured out they were 6.5x54mm Mannlicher-Schonauer rounds. https://en.wikipedia.org/wiki/6.5%C3%9754mm_Mannlicher%E2%80%93Sch%C3%B6nauer

So going off this, I had him send me a picture of the gun (it was super fuzzy so I didn't post it), and based on the extending metal infront of the trigger guard (the area where the clip sits, as it's a top loader), I deduced it must be an Italian Carcano, and the 6.5x54mm's wikipedia page mentioned that during German occupation, captured Carcano rifles were rechambered into that round for use by Greek forces. I sent him a few pictures of different Carcano rifles and he said the Model 1938 matched the curved bolt handle style his had.
https://en.wikipedia.org/wiki/Carcano
https://i.imgur.com/pdGo8XK.png

So I'm hoping this might be a rare rechambered gun; unfortunately, however, someone decided to mess with this gun. The front of the stock was cut down a few inches infront of that big trigger guard extension, and the original rear sight was replaced with a Williams rear sight (He has no idea what model of sight it is, it's just stamped). My dad thinks it might've been a war trophy, and it makes sense to me for how an Italian rifle rechambered in a hungarian round to end up in the US. He says the bolt action and firing pin both work, and he still has a clip for it and a few rounds, but he's too scared to try to fire a gun that old.

I'd love any feedback on this, such as if he's sitting on something worth a couple thousand dollars to a collector. I should hopefully be able to get better pictures, but his cellphone just can't seem to focus on an image.