File down any overhang of the full cock notch on the tumbler that protrudes beyond the sear nose. Some even reduce this to a thickness less than the sear nose for a hair trigger. I am not familiar with the Italian locks, so not sure about the sear nose, some of these are quite narrow and you certainly would not want to shave the tumbler too much. Polish all contacting surfaces with emory cloth including the interior lock plate, sear and tumbler. By simply performing these steps I have solved any heavy triggers I have come into contact with. As stated in another post regarding a Numrich Arms Minuteman, the geometry of the trigger itself can be an issue.