Dahlgren gun
Dahlgren guns were muzzle-loading naval guns designed by United States Navy Rear Admiral John A. Dahlgren (November 13, 1809 – July 12, 1870), mostly used in the American Civil War. Dahlgren's design philosophy evolved from an accidental explosion in 1849 of a 32 lb (14.5 kg) gun being tested for accuracy, killing a gunner.