Did Italy's 65 mm AA gun become effective?

Did the Italians get useful results from their wartime 65 mm medium AA gun?

Not to a significant extent; it remained a troubled compromise whose theoretical advantages did not outweigh reliability, production, and performance problems.

The weapon appeared attractive on paper, yet it did not establish a durable advantage over neighboring calibres. Its programme was cancelled in 1943 after only limited association with Capitani Romani designs. The 57 mm alternative offered a better rate of fire, while 76 mm weapons delivered a more useful explosive effect. Production difficulty further weakened a compromise that failed to provide the expected best of both worlds.