right|thumb|[[USS Iowa (BB-61)|USS ''Iowa'' (BB-61) fires a full broadside of 16&nbsp;in (406&nbsp;mm) guns.]]
A '''gun turret''' is a device that protects the crew or mechanism of a projectile firing weapon and at the same time lets the weapon be aimed and fired in many directions.

A turret is a rotating weapon platform. This can be mounted on a fortified military aircraft.

Turrets may be armed with one or more automatic cannons, large-calibre guns, or missile launchers. It may be manned or remotely controlled, and is often armoured. A small turret, or sub-turret on a larger one, is called a '''cupola'''. The term ''cupola'' also describes rotating turrets that carry no weapons but instead sighting devices, as in the case of tank commanders.  A finial is an extremely small sub-turret or sub-sub-turret mounted on a cupola turret.

The protection provided by the turret may be against battle damage or against the weather, conditions and environment in which the weapon or its crew operate.

The term comes from turret - a protective position on a fortification situated on top of a building or wall, as opposed to rising directly from the ground which is a tower.

==Warships==
===History===
thumb|300px|left|An animation showing the operating principle of a gun turret. This is based on the Mark I turret of the British [[BL 15 inch /42 naval gun; compare the layout and nomenclature with the American design below.]]
thumb|left|300px|Cutaway illustration of an American [[16"/50 caliber Mark 7 gun|16&nbsp;inch (40.6&nbsp;cm) gun turret]]

Before the development of large-calibre, long-range guns in the mid-19th century, the classic battleship design used rows of port-mounted guns on each side of the ship, often mounted in casemates. Firepower was provided by a large number of guns which could only be aimed in a limited arc from one side of the ship. Due to instability, fewer larger and heavier guns can be carried on a ship. Also, the casemates often sat near the waterline, which made them vulnerable to flooding and restricted their use to calm seas. Turrets allowed the smaller number of guns to be aimed and fired on both sides of the ship and at the same time provided armoured protection to the gun crew.

One of the earliest turret gun ships was the USS ''Monitor'', which mounted two muzzle loading cannons in a fully rotating armoured drum. An alternative at the time used a static drum, the barbette, inside which the gun mount rotated - the gun barrel projecting over the edge of the drum. In latter designs this was developed to have an armoured portion that sat over the gun and the edge of the barbette, leading to the term "hooded barbette".

With the advent of the HMS ''Dreadnought'' which, while revolutionary in many other ways, still retained wing turrets. The superfiring or superimposed arrangement had not been proven until after ''South Carolina'' went to sea, and it was initially feared that the weakness of the previous Virginia class ship's stacked turrets would repeat itself.

Another major advancement was in the Kongō class battlecruisers and Queen Elizabeth class battleships, which dispensed with the "Q" turret amidships in favour of heavier guns in fewer mountings.

While World War I ships commonly had a twin-turret configuration, ships by World War II were commonly using triple and even quadruple turrets, which reduced the total number of mountings altogether and improved armour protection, though quad mount turrets proved to be extremely complex to arrange, making them unwieldy in practice.

The largest warship turrets were in WWII battleships where a heavily armoured enclosure protected the large gun crew during battle. The calibre of the main armament on large battleships was typically 12&nbsp;in (30&nbsp;cm) up to 18&nbsp;in (45&nbsp;cm). The turrets carrying the 18-inch guns of ''Yamato'' each weighed around 2,500 tons(?). The secondary armament of battleships (or the primary armament of cruisers) was typically between 5 and 6&nbsp;in (127 - 152&nbsp;mm). Smaller ships typically mounted guns from 3&nbsp;in (76&nbsp;mm) upwards, although these rarely require a turret mounting.

===Layout===
In naval terms, a '''turret''' traditionally and specifically refers to a gun mounting where the entire mass rotates as one, and has a trunk that pierces the deck. The rotating part of a turret seen above deck is the gunhouse, which protects the mechanism and crew, and is where the guns are loaded. The gunhouse is supported on a bed of rotating rollers, and is not physically attached to the ship; were the ship to shell and magazines below. There may be a combined hoist (''cf'' the animated British turret) or separate hoists (''cf'' the American turret cutaway). The working chamber and trunk rotate with the gunhouse, and sit inside a protective armoured barbette. The barbette extends down to the main armoured deck (red in the animation). At the base of the turret sit handing rooms, where shell and propelling charges are passed from the shell room and magazine to the hoists.

The handling equipment and hoists are complex arrangements of machinery that transport the shells and charges from the magazine into the base of the turret. Bearing in mind that shells can weigh around a ton, the hoists have to be powerful and rapid; a 15&nbsp;inch turret of the type in the animation was expected to perform a complete loading and firing cycle in a minute<ref>Capt. S. W. Roskill, RN, ''HMS Warspite'', Classics of Naval Literature, Naval Institute Press, 1997 ISBN 1-55750-719-8</ref> The loading system is fitted with a series of mechanical interlocks that (in theory) ensure that there is never an open path from the gunhouse to the magazine down which an explosive flash might pass. Flash-tight doors and scuttles open and close to allow the passage between areas of the turret. Generally, with large-calibre guns, powered or assisted ramming is required to force the heavy shell and charge into the breech. As the hoist and breech must be aligned for ramming to occur, there is generally a restricted range of elevations at which the guns can be loaded; the guns return to the loading elevation, are loaded, then return to the target elevation. The animation illustrates a turret where the rammer is fixed to the cradle that carries the guns, allowing loading to occur across a wider range of elevations.

Earlier turrets differed significantly in their operating principles. It was not until the last of the "rotating drum" designs described in the previous section were phased out that the "hooded barbette" arrangement above became the defining turret.

====Wing turrets====
thumb|right|The late pre-dreadnought [[HMS Agamemnon (1906)|HMS ''Agamemnon'', with 9.2&nbsp;inch secondary guns shipped in wing turrets]]
thumb|right|The dreadnought battleship [[HMS Dreadnought (1906)|HMS ''Dreadnought'' had a main battery 12&nbsp;inch wing turret on either beam.]]
A '''wing turret''' is a gun turret mounted along the side, or the wings, of a warship, off of the centerline.

The positioning of a wing turret limits its arc of fire, so that it generally can contribute to only the HMS ''Dreadnought'' but not the SMS ''Blücher'', the wing turrets could fire fore and aft, so this somewhat reduced the danger of crossing the T and the turrets could fire to enemies at the rear.

Attempts were made to mount wing turrets ''en echelon'' so that they could fire on either beam, such as the Invincible and SMS ''Von der Tann'' battlecruisers, but this tended to cause great damage to the ships deck from the gun blast.

Wing turrets were commonplace on secondary battery of sub-calibre weapons. In large armoured cruisers, wing turrets contributed to the main battery, although the casemate mounting was more common. At the time, large numbers of smaller calibre guns contributing to the broadside were thought to be of great value in demolishing a ships upperworks and secondary armaments, as distances of battle were limited by fire control and weapon performance.

right|thumb|[[USS Iowa (BB-61)|USS ''Iowa'' (BB-61) menembakan kesamping meriam kaliber 16 inchi (406 mm).]]
'''Tempurung senjata''' atau gun turret dalam bahasa inggris adalah alat untuk melindungi para operator dan juga melindungi mekanisme penembakan peluru. Tempurung senjata juga biasanya berupa alat penopang senjata yang mampu berputar sehingga memungkinkan senjata ditembakkan ke segala arah.

Tempurung mampu di persenjatai dengan satu atau banyak senjata, meriam, mortir, roket maupun rudal. Tempurung senjata bisa di awaki manusia tetapi bisa pula dikendalikan dari jarak jauh. Tempurung biasanya mempunyai lapisan baja. Tempurung senjata yang kecil atau tempurung senjata yang terpasang pada sebuah tempurung yang lebih besar kerap disebut kupola. Sebutan Kupola juga bisa digunakan untuk menyebut tempurung kecil yang tidak berisi senjata tetapi hanya berupa peralatan pengamatan (contohnya adalah Kupola utnuk komandan tank). sedangkan Finial adalah sebuah tempurung yang sangat kecil atau menumpang pada sebuah Kupola.

Perlindungan yang diberikan oleh tempurung senjata adalah perlindungan terhadap kerusakan pertempuran, cuaca atau kondisi lingkungan.
== Pembagian ruangan dalam turret meriam kaliber 15 inchi ==
right|300px|Animasi mekanisme kerja tempurung senjata
Sebuah tempurung senjata terdiri dari:
#Dek
#Ruang peluru
#Dek bawah
#Magasin
#Dek tengah
#Bagasi
#Dek utama
#Barbette
#Bilik kerja
#dek atas
#Jalur penggelinding
#Ayunan
#Rumah senjata