Bombardment of Kagoshima
The armament of the "Hector"-class ships was intended to be 32 smoothbore, muzzle-loading 68-pounder guns, 15 on each side on the main deck and one each fore and aft as chase guns on the upper deck. This was modified during "Hector"s construction to four rifled 110-pounder breech-loading guns mounted on the upper deck and twenty-four 68-pounders on the broadside. "Valiant", due to the delays in her construction and a shortage of guns, never received any of these guns. The breech-loading guns were a new design from Armstrong and much was hoped for them. To partially alleviate their overweight condition the ships were not fully armed and only received four 110-pounders on the upper deck and twenty 68-pounders on the main deck behind armour. Firing tests carried out in September 1861 against an armoured target, however, proved that the 110-pounder was inferior to the 68-pounder smoothbore gun in armour penetration and repeated incidents of breech explosions during the Battles for Shimonoseki and the Bombardment of Kagoshima in 1863–64 caused the navy to withdraw the gun from service shortly afterwards.