The Strong Firearms Company operated in New Haven, Conn. from 1878-1890. Originally named the Strong Ammunition Company it became the Strong Firearms Company with the sale of the ammunition division to Winchester Repeating Arms Company in 1884. They became a major manufacturer of muzzle-loading and breech-loading signal and salute cannon with some incidental production of single-shot rifles and shotguns which are now considered scarce.
Very nice images!, Looks like a well made firearm, I have never seen a standing breach lock up like this one, looks like it would hold almost any cartridge of the day and even some modern cartridge's.