Italian soldiers of the 33ª Divisione fanteria "Acqui" (33rd Mountain Infantry Division Acqui) and Carabinieri units (military police) are correctly armed with Carcano M91/38 Cavalry Carbine and artillery/cavalry bandoleers. Like most of the weapons in the movie, patisans are armed with this rifle. Captain Antonio Corelli (Nicolas Cage) is seen with a Carcano rifle when german troops attack the italian division.
Carcano Moldello 91
Some italian troops are seen to use Carcano Modello 91 rifles. The 91 was the main rifle of the Italian infantry since 1891 (when he replaced the Vetterli) until the Second World War. Excluding the troops that specifically required a shorter rifle, the 91 long rifle equipped the majority of the Italian army during both world wars.
Karabiner 98k
Wehrmacht and partisans are mainly armed with K98K rifles.
Italian infantry, Carabinieri and partisans, including Captain Corelli (Nicolas Cage) and Mandras (Christian Bale), use Moschetto Automatico Beretta 38 SMGs. This is not entirely correct, because the weapon was mainly reserved for special forces or police units (like Carabinieri or Royal Guardia di Finanza in the case of Cephalonia) and only small part to infantry divisions.
MP38
The soldier who threatened the Captain Corelli is armed with a MP38.
MP40
Many of the wehrmacht soldiers are armed with MP40.
Breda Modello 37
Italians use Breda Modello 37 light machineguns. This is historically correct, but Model 37s would have to be accompanied by a considerable number of Model 30s.