Franchi
If it were a 48 AL that you were asking about, then I could tell you a story or two.
The 520 is, iirc, gas operated, though I recently saw a note about it being an inertia action....I believe that is wrong though the current crop of Franchis are apparently inertia actions.
The 48 AL is described as "long recoil action similar to the iconic Browning A5.
Pete
