World War I 8,000 m (5.0 mi) Grenade The Canon de 24 C modèle 1864 was a cast iron rifled breech loader built-up gun used by the French Navy and as coastal artillery.

The first rifled gun of the French navy was the Canon de 16 cm modèle 1855.

They were hooped with steel bands and fired a cylindrical projectile of about twice the weight of the round bullet.

[3] During the March 1862 Battle of Hampton Roads, both the Unionist smoothbore 280 mm Dahlgren guns and the Confederate 7 inch Brooke rifles proved unable to effectively deal with armored opponents.

In a June 1866 session of the French Parliament, Henri Dupuy de Lôme gave some details about the rifled modèle 1864 guns that were being developed.

Dupuy de Lôme then said that the 24 cm gun was the heaviest piece intended for use on board, and that it weighed 14,000 kg.

[7] In a work printed in 1867, the 24 cm modèle 1864 gun was said to be 4.56 m long, to have a diameter of 0.98 m at the breech, and to weigh 14,000 kg.

One of the drawings published on account of the exhibition shows an early model of the barrel of the 24 cm modèle 1864.

The primary change consisted of boring up the barrel and introducing a steel inner tube through the muzzle.

In the end, the barrels with an à coin breech were not put into service and were modified.

[15] Ignition of the charge took place via a traditional hold drilled towards the chamber at 500 mm before the breech.

[20] The above engraving published about the gun as shown at the 1867 Paris World's Fair has very strong similarities to this description.

The one near the muzzle had a tronconic side to make the transition to the barrel and had a shoulder for the first ring of the second layer.

[21] In general, the weight of the projectiles was twice that of the solid round cast iron shot for the caliber.

[24] The chilled cast iron armor piercing grenade obus oblong en fonte dure was about L/2.5 long.

[23] It was modeled on the steel shot, but was longer to compensate for the lower density of cast iron.

[12] The velocity at which an armor-piercing projectile left the barrel of the gun was crucial for its ability to penetrate armor.

[8] In the early 1880s, the charge for the armor piercing shot (projectile de rupture) was given as 24 kg.

For the Canon de 24 C modèle 1864 T. 70, the charge for the armor piercing grenade was given as 41.5 kg and velocity was 480 m/s.

At the maximum range of about 8 km, the flight of the projectile took about 45 seconds, during which the wind would blow it off course.

[28] The ballistic tables of the 24 cm gun gave its ranges for the different projectiles, charges and elevations.

It could therefore be fired at a higher elevation, relying on the explosive charge of the grenade to damage the target.

[12] In December 1867, the Dutch government appointed a commission to investigate the possibilities to quickly acquire heavy coastal guns.

The breech should be made by Varral, Elwell & Poulot in Paris, and the whole should be assembled in Sweden.

To protect the accesses to Rotterdam, 4 guns would be placed in Brielle; 13 in Hellevoetsluis; and 20 in Willemstad, North Brabant.

In 1869, Gloire's 34 battery deck guns were replaced by six Canon de 24 C modèle 1864.

The United States monitor Onondaga was re-armed with four Canon de 24 C modèle 1864 after she was acquired by France in May 1867.

[42] On land, the Canon de 24 C modèle 1864 was of course used to arm a number of coastal defense batteries.

The 24 cm ijzer in the Nationaal Militair Museum of the Netherlands was originally placed at Willemstad.

It was damaged when the previous artillery museum at Doorwerth Castle came under fire during the 1944 Operation Market Garden.