used against ships which were already stopped dead in the water. The ram finally fell out of favour in the 1880s, as the same effect could be achieved with a torpedo, with less vulnerability to quick-firing guns. Development of naval guns The armament of ironclads tended to become concentrated in a small number of powerful guns capable of penetrating the armor of enemy ships at range; calibre and weight of guns increased markedly to achieve greater penetration. Throughout the ironclad era navies also grappled with the complexities of rifled versus smoothbore guns and breech-loading versus muzzle-loading. carried a mixture of 110-pounder breech-loading rifles and more traditional 68-pounder smoothbore guns. Warrior highlighted the challenges of picking the right armament; the breech-loaders she carried, designed by Sir William Armstrong, were intended to be the next generation of heavy armament for the Royal Navy, but were shortly withdrawn from service. Breech-loading guns seemed to offer important advantages. A breech-loader could be reloaded without moving the gun, a lengthy process particularly if the gun then needed to be re-aimed. Warriors Armstrong guns also had the virtue of being lighter than an equivalent smoothbore and, because of their rifling, more accurate. Nonetheless, the design was rejected because of problems which plagued breech-loaders for decades. The weakness of the breech-loader was the obvious problem of sealing the breech. All guns are powered by the explosive conversion of a solid propellant into gas. This explosion propels the shot or shell out of the front of the gun, but also imposes great stresses on the gun-barrel. If the breech—which experiences some of the greatest forces in the gun—is not entirely secure, then there is a risk that either gas will discharge through the breech or that the breech will break. This in turn reduces the muzzle velocity of the weapon and can also endanger the gun crew. Warriors Armstrong guns suffered from both problems; the shells were unable to penetrate the armor of Gloire, while sometimes the screw which closed the breech flew backwards out of the gun on firing. Similar problems were experienced with the breech-loading guns which became standard in the French and German navies. These problems influenced the British to equip ships with muzzle-loading weapons of increasing power until the 1880s. After a brief introduction of the 100-pounder or smoothbore Somerset Gun, which weighed , the Admiralty introduced 7-inch (178 mm) rifled guns, weighing .