See pic . I can email more pictures if needed.

I believe this is a Mediterranean spring-powered speargun from the 1950s, possibly Italian or French in origin. The features match several brands of that era — the brass barrel with anti-suction slots, the flat metal pistol-grip handle, and the two-pronged barbed spear tip are all consistent with Italian makers like Cressi, Aquatic, or Siama, or French equivalents.

Italian manufacturers of that era, such as Aquatic in Genoa, produced spring spearguns ranging from 110–200cm, while companies like Siama presented the Barracuda with spring, followed by models "embellished by brass particulars."