Bullet diameter is far too small for an italian Carcano FMJ bullet. I agree with you, it is not italian, according to me.
We ( italian researchers) suspect that the rare italian Carcano match cartridges used Swedish bullets, but they were pointed ones and were loaded by Pirotecnico of Bologna in 1933 and 1934 only.
The bulge often comes out when you put a bullet into a Carcano case with the “step” inside the neck. The base of the bullet rests against this step and can’t enter inside the case.That step is at the end of the neck in ordinary cartridges, in the middle of the neck in frangible / short range cartridges and is absent in “mitraglia” loadings, where a smaller diameter bullet is used.
If the base of the bullet ( or not the proper bullet is used) passes this step, the result is a bulge on the neck.