I photographed this Breech Loading 5.5-in. Mk. 1 WWI-era naval gun at the Imperial War Museum’s location in London. The British Royal Navy was happy with the performance of the gun as it was significantly lighter than the standard 6-inch gun and fired an 82 lb shell rather than the 100 lb shell of the 6-inch weapon. It, therefore, had a higher rate of fire with little loss in hitting power.
This particular gun was off of the HMS Chester. Boy Seaman First Class Jack Cornwell was posthumously awarded the Victoria Cross for heroism in serving his gun on HMS Chester during the Battle of Jutland on 31 May 1916.