Why large muzzle-loading guns persisted

Loading from the breech reduced the need to expose crews or build turrets large enough to draw an entire gun inward. Contemporary gun construction was itself changing as larger powder chambers and longer barrels extracted more force from each charge. Higher pressures made breech failure especially concerning in large naval weapons, even when smaller breech loaders appeared practical. The Royal Navy consequently retained the rifled muzzle-loading 12-inch 35-ton gun across several classes. Elswick had advertised a proved 12-inch breech loader since 1877, meaning it had passed a set of firing tests, and Woolwich began work on another in 1879. The chronology runs from the Devastation class in 1873 through Ajax in 1880, with the Colossus class adopting a 12-inch breech loader in 1882.