Naval Gun Barrel

Naval Gun Barrel. . , Naval Gun Barrel 4.5 inch QF Mk III , Calibre 114mm (4.5 inch) , Range 18.2 km (19,990 yards) , Anti Aircraft Ceiling 9.1km (29,900 feet) , Rate of Fire 14 rounds per minute , Shell weight 25 kg (55lb) , , In the 1930s a Naval gun was required that could operate against both shipping and aircraft. After some experimentation a calibre of 4.5 inches was chosen. For speed of loading, a fixed round was required where the shell is attached to a brass cartridge case in the manner of a bullet. , , By 1934 the army were also looking for a new heavy anti aircraft gun and in 1938 adopted the Navy's 4.5 inch. The gun was deployed for home defence and became the standard heavy gun of the Battle of Britain. As the war progressed simple computers and specialised ‘proximity’ fuses were developed which improved the effectiveness of the gun, by the end of the war anti aircraft artillery had become almost entirely automated. , , In 1943 the barrels were re-lined to the smaller calibre of 3.7 inch creating a very powerful weapon, known as the 3.7 inch Mk 6. , , A similar barrel can be seen mounted in the turret in the No. 2 gun emplacement.