What proof marks are on the gun? That would help with identification.
In my Side by Sides of the World by Charles Carder there are two listings for Hackett.
HACKETT, EDWIN; Maker of high quality breech loading hammer double barrel shotguns, located in New York City circa 1879 to 1885.
HACKETT, EDWIN & GEORGE; Of London, England, circa 1870. No other history known.
A connection between the two is unknown.
