John Adolphus Bernard Dahlgren was a United States Navy officer who founded his service's Ordnance Department and launched significant advances in gunnery.
Dahlgren during the American Civil War
Rear Admiral Dahlgren, on board the USS Pawnee, beside a 50-pounder Dahlgren rifle, one of his bottle-shaped cast-iron cannons, c. 1864
Dahlgren during the American Civil War
Dahlgren's tombstone in Laurel Hill Cemetery in Bala Cynwyd, Pennsylvania
Dahlgren guns were muzzle-loading naval gun designed by Rear Admiral John A. Dahlgren USN, mostly used in the period of 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. He believed a safer, more powerful naval cannon could be designed using more scientific design criteria. Dahlgren guns were designed with a smooth curved shape, equalizing strain and concentrating more weight of metal in the gun breech where the greatest pressure of expanding propellant gases needed to be met to keep the gun from bursting. Because of their rounded contours, Dahlgren guns were nicknamed "soda bottles", a shape which became their most identifiable characteristic.
John A. Dahlgren standing next to a 50 lb (22.7 kg) Dahlgren rifle aboard USS Pawnee in 1865
A 9 in (229 mm) Dahlgren smoothbore naval gun and crew in the stern pivot position of USS Miami, 1864. (National Archives).
Dahlgren boat howitzer mounted in frigate's launch. The field carriage can be seen in stern
Dahlgren boat howitzer mounted on field carriage
