Both in the Italian OOB and in the Italian Social Republic (04 and 34) there is a 75mm L60 Mod.34 (weapon 115), used in both OOB`s as a heavy AT gun.
Shouldn`t this gun have a barrel length of L46 with accuracy of 12 instead of 15? I`m quite sure this gun is meant:
https://en.wikipedia.org/wiki/Cannon....A._modello_34
which was an AAA, used also in the AT-role.
Otherwise I have no information about a 75mm gun with L60 in Italian service.
Cheers