i have always been interested in martinis because my father has always had them .i have one round for a harpoon gun which is small. i have only seen one on movie JAWS which i believe were nickel plated , and on large (577/450) action can anyone enlighten me further on these guns?

Would this be anything like a line throwing gun? The US Navy used 45-70 line throwing guns.

i believe navy arms company in ridgefield new jersey still market these harpoon guns.