Known as The ''Rockbuster'', The British 100-Ton Gun was designed by William Armstrong (inventor of The ''Armstrong'' Cannon). (15) Models were built between 1877 and 1906. These Guns were designed primarily as Coastal Defense weapons. A slightly smaller version was designed for use with some of the earlier Classes of ''Dreadnaught'' warships.
Weighing 100-tons, the massive piece was 30-feet in length. As a fixed Fortification Gun, The ''Rockbuster'' (as it was called), could fire a 2,000-lb. Shell (HE), to a range of 6,000-yards. A typical Crew consisted of (35) Men (18 of which were needed to handle and load The Shell). A rate of fire of (1) every 6-minutes was prescribed. The ''Rockbuster'' was retired in 1906.