[Max in Utah]

I don’t know that carbine, but wasn’t it possible for Oswald to have disassembled the stock from the barrel?

Dismounting the barrel/action from the stock could have easily shortened the package by 12" or more.

[Max in Utah]

Oops, correction: it would shorten the package if the rifle had been "sporterized" (forward part of the stock shortened). It appears that the Carcano found in the Book Depository was not altered in this fashion.

Looking at the picture, it appears that disassembling the rifle would only shorten a package by 4-5".