I have a little experience in this area.
Re neck-resizing to save your cases from premature death, you can use standard dies. Just unscrew the resizing die and screw it back in only enough to touch the upper half of the case neck. You may want to use a candle to put some soot on a test cartridge case or two to ensure you are not touching the shoulder or the base of the cartridge case itself when the press ram is as far up as it can travel. Another hint: take out the expander button. This will often stretch case necks, and cases, when the ram is withdrawn. Use a few empty cases with just a bullet to make up some test rounds... you can use a bullet puller to try again, and you'll know you have it right when the test cartridge will chamber and eject. BTW you can use the soot trick to ensure the bullet is seated as far out as it can without touching the lands... you want a little bit of a gap, at least 0.010"... and you also want it to feed through the magazine.
Of course, you might want to use a runout gauge on a fired case to see if your Carcano's chamber is concentric. Some of the Axis WWII rifles, especially those made later in the conflict, or rebarrelled later on, have quality control issues... and as long as the gun went BANG and could hit a dinner plate at 100 yards, it was good enough.
Be mindful about case stretching and resultant high pressures... you should check for max case length and trim cases accordingly. Military chambers are notorious for sloppiness because absolute reliability was more important than absolute accuracy and cartridge case life. Also, if you get three or four firings out of a cartridge case in a military surplus rifle, that's enough to have reduced the cost of the case to way less than the bullet on a per-shot basis. There's a lot of pressure in a centerfire rifle cartridge once that trigger has been pulled, and that case is the only thing it and your face.
Everything is on its way to somewhere...