I have a Budapest (FEG) M.95 stutzen carbine and can confirm that they are fairly unpleasant to shoot. Also likely the least accurate bolt action rifle I have ever fired. It's fun though, in the same way that all short-barreled carbines in full powered rifle rounds are - giant muzzle blast, bullet comes flying out and goes... somewhere roughly in the direction you aimed, big hole. The straight pull action is mechanically interesting, although I'm not really convinced it allows you to fire any faster than a normal turn bolt.
Ammo is actually not super hard to find - PPU makes new production, although it's a little expensive (IME about $24 for a box of 20 rounds). In my area, I also occasionally see old pre-WWII Austrian 8x56R packs, which come in little triangular cardboard boxes of 10 rounds on chargers and look like this:
View attachment 1469400
I've bought these within the past year for as low as $10 each. Although like any old surplus ammo, they have a pretty high misfire rate - I think about 1 in 4 of the rounds I've shot of this type failed to fire, and it's always a little uncomfortable when you pull the trigger and nothing happens and then you just have to sit and wait.
The absolute worst thing about the M.95 is the disassembly. The bolt can only be put in or taken out of the receiver when the internal and external camming surfaces are in the open position, but once the bolt is out of the gun, lightly breathing on it will make it collapse into the closed position. Returning it to the open position frequently requires jamming something into the bolt mechanism to hold the two pieces apart (a US dime is the perfect size).
Edit to add: the real unicorn ammo which I have resigned myself to never finding is 8x50R Siamese for my Type 46. I don't think I'll ever be able to shoot that thing unless I take up hand loading in the future.