A firearm is a portable gun (a barreled ranged weapon) that inflicts damage on targets by launching one or more projectiles driven by rapidly expanding high-pressure gas produced chemically by exothermic combustion (deflagration) of propellant within an ammunition cartridge.[1][2][3]  If gas pressurization is achieved through mechanical gas compression rather than through chemical propellant combustion, then the gun is technically an air gun, not a firearm.[4]
The first primitive firearms originated in 10th-century China when bamboo tubes containing gunpowder and pellet projectiles were mounted on spears into the one-person-portable fire lance,[5] which was later used as a shock weapon to good effect in the Siege of De'an in 1132. In the 13th century the Chinese invented the metal-barrelled hand cannon, widely considered the true ancestor of all firearms.  The technology gradually spread through the rest of East Asia, South Asia, the Middle East, and Europe. Older firearms typically used black powder as a propellant, but modern firearms use smokeless powder or other propellants. Most modern firearms (with the notable exception of smoothbore shotguns) have rifled barrels to impart spin to the projectile for improved flight stability.
Modern firearms can be described by their caliber (i.e. their bore diameter; this is given in millimeters or inches e.g. 7.5mm, .357 in.) or in the case of shotguns their gauge (e.g. 12 ga.); by the type of action employed (muzzle, breech, lever, bolt, pump, revolver, semi-automatic, automatic etc.) together with the usual means of deportment (hand-held or mechanical mounting). Further classification may make reference to the type of barrel used (rifled) and to the barrel length (24 inch), to the firing mechanism (e.g. matchlock, wheellock, flintlock, percussion lock), to the design's primary intended use (e.g. hunting rifle), or to the commonly accepted name for a particular variation (e.g. Gatling gun).
Shooters aim firearms at their targets with hand-eye coordination, using either iron sights or  optical sights. The accurate range of pistols generally does not exceed 110 yards (100m), while most rifles are accurate to 550 yards (500m) using iron sights, or to longer ranges using optical sights (firearm rounds may be dangerous or lethal well beyond their accurate range; the minimum distance for safety is much greater than the specified range). Purpose-built sniper rifles and anti-materiel rifles are accurate to ranges of more than 2,200 yards (2,000m).

Types of firearms
Firearms include a variety of ranged weapons and there is no agreed upon definition. Many soldiers consider a firearm to be any ranged weapon that uses gunpowder or a derivative as a propellant.
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Small arms

Small arms include handguns (revolvers and pistols) and long guns, such as rifles, carbines, shotguns, submachine guns, assault rifles, battle rifles, personal defense weapons, and light machine guns.
The world's top small arms manufacturing companies are Browning, Remington, Colt, Ruger, Smith & Wesson, Savage, Mossberg (USA), Heckler & Koch, SIG Sauer, Walther (Germany), Glock, Steyr-Mannlicher (Austria), FN Herstal (Belgium), Beretta (Italy), Norinco (China), Tula Arms and Kalashnikov (Russia), while former top producers were Mauser & Springfield Armory.
In 2018, Small Arms Survey reported that there are over one billion small arms distributed globally, of which 857 million (about 85 percent) are in civilian hands.[6][7] U.S. civilians alone account for 393 million (about 46 percent) of the worldwide total of civilian held firearms.[7] This amounts to "120.5 firearms for every 100 residents."[7] The world's armed forces control about 133 million (about 13 percent) of the global total of small arms, of which over 43 percent belong to two countries: the Russian Federation (30.3 million) and China (27.5 million).[6] Law enforcement agencies control about 23 million (about 2 percent) of the global total of small arms.[6]
Handguns

The smallest of all firearms is the handgun. There are two common types of handguns: revolvers and semi-automatic pistols. Revolvers have a number of firing chambers or "charge holes" in a revolving cylinder; each chamber in the cylinder is loaded with a single cartridge or charge. Semi-automatic pistols have a single fixed firing chamber machined into the rear of the barrel, and a magazine so they can be used to fire more than one round. Each press of the trigger fires a cartridge, using the energy of the cartridge to activate the mechanism so that the next cartridge may be fired immediately. This is opposed to "double-action" revolvers which accomplish the same end using a mechanical action linked to the trigger pull.
Prior to the 19th century, virtually all handguns were single-shot muzzleloaders. With the invention of the revolver in 1818, handguns capable of holding multiple rounds became popular. Certain designs of auto-loading pistol appeared beginning in the 1870s and had largely supplanted revolvers in military applications by the end of World War I. By the end of the 20th century, most handguns carried regularly by military, police and civilians were semi-automatic, although revolvers were still widely used. Generally speaking, military and police forces use semi-automatic pistols due to their high magazine capacities and ability to rapidly reload by simply removing the empty magazine and inserting a loaded one. Revolvers are very common among handgun hunters because revolver cartridges are usually more powerful than similar caliber semi-automatic pistol cartridges (which are designed for self-defense) and the strength, simplicity and durability of the revolver design is well-suited to outdoor use. Revolvers, especially in .22 LR and 38 Special/357 Magnum, are also common concealed weapons in jurisdictions allowing this practice because their simple mechanics make them smaller than many autoloaders while remaining reliable. Both designs are common among civilian gun owners, depending on the owner's intention (self-defense, hunting, target shooting, competitions, collecting, etc.).
Long guns

A long gun is generally any firearm that is larger than a handgun and is designed to be held and fired with both hands, either from the hip or the shoulder. Long guns typically have a barrel between 10 and 30 inches (there are restrictions on minimum barrel length in many jurisdictions; maximum barrel length is usually a matter of practicality), that along with the receiver and trigger group is mounted into a wood, plastic, metal or composite stock, composed of one or more pieces that form a foregrip, rear grip, and optionally (but typically) a shoulder mount called the butt. Early long arms, from the Renaissance up to the mid-19th century, were generally smoothbore firearms that fired one or more ball shot, called muskets or arquebus depending on caliber and firing mechanism.
Rifles and shotguns

Most modern long guns are either rifles or shotguns. Both are the successors of the musket, diverging from their parent weapon in distinct ways. A rifle is so named for the spiral fluting (rifling) machined into the inner surface of its barrel, which imparts a self-stabilizing spin to the single bullets it fires. Shotguns are predominantly smoothbore firearms designed to fire a number of shot; pellet sizes commonly ranging between 2mm #9 birdshot and 8.4mm #00 (double-aught) buckshot. Shotguns are also capable of firing single slugs, or specialty (often "less lethal") rounds such as bean bags, tear gas or breaching rounds. Rifles have a very small impact area but a long range and high accuracy. Shotguns have a large impact area with considerably less range and accuracy. However, the larger impact area can compensate for reduced accuracy, since shot spreads during flight; consequently, in hunting, shotguns are generally used for flying game.
Rifles and shotguns are commonly used for hunting and often to defend a home or place of business. Usually, large game are hunted with rifles (although shotguns can be used, particularly with slugs), while birds are hunted with shotguns. Shotguns are sometimes preferred for defending a home or business due to their wide impact area, multiple wound tracks (when using buckshot), shorter range, and reduced penetration of walls (when using lighter shot), which significantly reduces the likelihood of unintended harm, although the handgun is also common.
There are a variety of types of rifles and shotguns based on the method they are reloaded. Bolt-action and lever-action rifles are manually operated. Manipulation of the bolt or the lever causes the spent cartridge to be removed, the firing mechanism recocked, and a fresh cartridge inserted. These two types of action are almost exclusively used by rifles. Slide-action (commonly called 'pump-action') rifles and shotguns are manually cycled by shuttling the foregrip of the firearm back and forth. This type of action is typically used by shotguns, but several major manufacturers make rifles that use this action.
Both rifles and shotguns also come in break-action varieties that do not have any kind of reloading mechanism at all but must be hand-loaded after each shot. Both rifles and shotguns come in single- and double-barreled varieties; however due to the expense and difficulty of manufacturing, double-barreled rifles are rare. Double-barreled rifles are typically intended for African big-game hunts where the animals are dangerous, ranges are short, and speed is of the essence. Very large and powerful calibers are normal for these firearms.
Rifles have been in nationally featured marksmanship events in Europe and the United States since at least the 18th century, when rifles were first becoming widely available. One of the earliest purely "American" rifle-shooting competitions took place in 1775, when Daniel Morgan was recruiting sharpshooters in Virginia for the impending American Revolutionary War. In some countries, rifle marksmanship is still a matter of national pride. Some specialized rifles in the larger calibers are claimed to have an accurate range of up to about 1 mile (1,600m), although most have considerably less. In the second half of the 20th century, competitive shotgun sports became perhaps even more popular than riflery, largely due to the motion and immediate feedback in activities such as skeet, trap and sporting clays.
In military use, bolt-action rifles with high-power scopes are common as sniper rifles, however by the Korean War the traditional bolt-action and semi-automatic rifles used by infantrymen had been supplemented by select-fire designs known as "automatic rifles".
Carbines

A carbine is a firearm similar to a rifle in form and intended usage, but generally shorter or smaller than the typical "full-size" hunting or battle rifle of a similar time period, and sometimes using a smaller or less-powerful cartridge. Carbines were and are typically used by members of the military in roles that are expected to engage in combat, but where a full-size rifle would be an impediment to the primary duties of that soldier (vehicle drivers, field commanders and support staff, airborne troops, engineers, etc.). Carbines are also common in law enforcement and among civilian owners where similar size, space and/or power concerns may exist. Carbines, like rifles, can be single-shot, repeating-action, semi-automatic or select-fire/fully automatic, generally depending on the time period and intended market. Common historical examples include the Winchester Model 1892, Lee–Enfield "Jungle Carbine", SKS, M1 carbine (no relation to the larger M1 Garand) and M4 carbine (a more compact variant of the current M16 rifle). Modern U.S. civilian carbines include compact customizations of the AR-15, Ruger Mini-14, Beretta Cx4 Storm, Kel-Tec SUB-2000, bolt-action rifles generally falling under the specifications of a scout rifle, and aftermarket conversion kits for popular pistols including the M1911 and Glock models.
Machine guns

A machine gun is a fully automatic emplaceable weapon, most often separated from other classes of automatic weapon by the use of belt-fed ammunition (though some designs employ drum, pan or hopper magazines), generally in a rifle-inspired caliber ranging between 5.56×45mm NATO (.223 Remington) for a light machine gun to as large as .50 BMG or even larger for crewed or aircraft weapons. Although not widely fielded until World War I, early machine guns were being used by militaries in the second half of the 19th century. Notables in the U.S. arsenal during the 20th century included the M2 Browning .50 caliber heavy machine gun and M1919 Browning .30 caliber medium machine gun, and the M60 7.62×51mm NATO general-purpose machine gun which came into use around the Vietnam War. Machine guns of this type were originally defensive firearms crewed by at least two men, mainly because of the difficulties involved in moving and placing them, their ammunition, and their tripod. In contrast, modern light machine guns such as the FN Minimi are often wielded by a single infantryman. They provide a large ammunition capacity and a high rate of fire, and are typically used to give suppressing fire during infantry movement. Accuracy on machine guns varies based on a wide number of factors from design to manufacturing tolerances, most of which have been improved over time. Machine guns are often mounted on vehicles or helicopters, and have been used since World War I as offensive firearms in fighter aircraft and tanks (e.g. for air combat or suppressing fire for ground troop support).
The definition of machine gun is different in U.S. law. The National Firearms Act and Firearm Owners Protection Act define a "machine gun" in the United States code Title 26, Subtitle E, Chapter 53, Subchapter B, Part 1, § 5845 as:
"... any firearm which shoots ... automatically more than one shot, without manual reloading, by a single function of the trigger". "Machine gun" is therefore largely synonymous with "automatic weapon" in the U.S. civilian parlance, covering all automatic firearms.
Submachine guns

A submachine gun is a magazine-fed firearm, usually smaller than other automatic firearms, that fires pistol-caliber ammunition; for this reason certain submachine guns can also be referred to as machine pistols, especially when referring to handgun-sized designs such as the Škorpion vz. 61 and Glock 18. Well-known examples are the Israeli Uzi and Heckler & Koch MP5 which use the 9×19mm Parabellum cartridge, and the American Thompson submachine gun which fires .45 ACP. Because of their small size and limited projectile penetration compared to high-power rifle rounds, submachine guns are commonly favored by military, paramilitary and police forces for close-quarters engagements such as inside buildings, in urban areas or in trench complexes.
Submachine guns were originally about the size of carbines. Because they fire pistol ammunition, they have limited long-range use, but in close combat can be used in fully automatic in a controllable manner due to the lighter recoil of the pistol ammunition. They are also extremely inexpensive and simple to build in time of war, enabling a nation to quickly arm its military. In the latter half of the 20th century, submachine guns were being miniaturized to the point of being only slightly larger than some large handguns. The most widely used submachine gun at the end of the 20th century was the Heckler & Koch MP5. The MP5 is actually designated as a "machine pistol" by Heckler & Koch (MP5 stands for Maschinenpistole 5, or Machine Pistol 5), although some reserve this designation for even smaller submachine guns such as the MAC-10 and Glock 18, which are about the size and shape of pistols.
Automatic rifles

An automatic rifle is a magazine-fed firearm, wielded by a single infantryman, that is chambered for rifle cartridges and capable of automatic fire. The M1918 Browning Automatic Rifle was the first U.S. infantry weapon of this type, and was generally used for suppressive or support fire in the role now usually filled by the light machine gun. Other early automatic rifles include the Fedorov Avtomat and the Huot Automatic Rifle. Later, German forces fielded the Sturmgewehr 44 during World War II, a light automatic rifle firing a reduced power "intermediate cartridge". This design was to become the basis for the "assault rifle" subclass of automatic weapons, as contrasted with "battle rifles", which generally fire a traditional "full-power" rifle cartridge.
Assault rifles

In World War II, Germany introduced the StG 44, and brought to the forefront of firearm technology what eventually became the class of firearm most widely adopted by the military, the assault rifle. An assault rifle is usually slightly smaller than a battle rifle such as the Karabiner 98k, but the chief differences defining an assault rifle are select-fire capability and the use of a rifle round of lesser power, known as an intermediate cartridge.
Soviet engineer Mikhail Kalashnikov quickly adapted the German concept, using a less-powerful 7.62×39mm cartridge derived from the standard 7.62×54mmR Russian battle rifle round, to produce the AK-47, which has become the world's most widely used assault rifle. Soon after World War II, the Automatic Kalashnikov AK-47 assault rifle began to be fielded by the Soviet Union and its allies in the Eastern Bloc, as well as by nations such as China, North Korea, and North Vietnam.
In the United States, the assault rifle design was later in coming; the replacement for the M1 Garand of WWII was another John Garand design chambered for the new 7.62×51mm NATO cartridge; the select-fire M14, which was used by the U.S. military until the 1960s. The significant recoil of the M14 when fired in full-automatic mode was seen as a problem as it reduced accuracy, and in the 1960s it was replaced by Eugene Stoner's AR-15, which also marked a switch from the powerful .30 caliber cartridges used by the U.S. military up until early in the Vietnam War to the much less powerful but far lighter and light recoiling .223 caliber (5.56mm) intermediate cartridge. The military later designated the AR-15 as the "M16". The civilian version of the M16 continues to be known as the AR-15 and looks exactly like the military version, although to conform to B.A.T.F.E. regulations in the U.S., it lacks the mechanism that permits fully automatic fire.
Variants of both of the M16 and AK-47 are still in wide international use today, though other automatic rifle designs have since been introduced. A smaller version of the M16A2, the M4 carbine, is widely used by U.S. and NATO tank and vehicle crews, airbornes, support staff, and in other scenarios where space is limited. The IMI Galil, an Israeli-designed weapon based on the action of the AK-47, is in use by Israel, Italy, Burma, the Philippines, Peru, and Colombia. Swiss Arms of Switzerland produces the SIG SG 550 assault rifle used by France, Chile, and Spain among others, and Steyr Mannlicher produces the AUG, a bullpup rifle in use in Austria, Australia, New Zealand, Ireland, and Saudi Arabia among other nations.
Modern designs call for compact weapons retaining firepower. The bullpup design, by mounting the magazine behind the trigger, unifies the accuracy and firepower of the traditional assault rifle with the compact size of the submachine gun (though submachine guns are still used); examples are the French FAMAS and the British SA80.
Personal defense weapons

A recently developed class of firearm is the personal defense weapon or PDW, which is in simplest terms a submachine gun designed to fire ammunitions with ballistic performance similar to rifle cartridges.  While a submachine gun is desirable for its compact size and ammunition capacity, its pistol cartridges lack the penetrating capability of a rifle round.  Conversely, rifle bullets can pierce light armor and are easier to shoot accurately, but even a carbine such as the Colt M4 is larger and/or longer than a submachine gun, making it harder to maneuver in close quarters.  The solution many firearms manufacturers have presented is a weapon resembling a submachine gun in size and general configuration, but which fires a higher-powered armor-penetrating round (often specially designed for the weapon), thus combining the advantages of a carbine and submachine gun.  This also earned the PDWs an infrequently used nickname — the submachine carbines.  The FN P90 and Heckler & Koch MP7 are most famous examples of PDWs.
Function

Firearms are also categorized by their functioning cycle or "action" which describes its loading, firing, and unloading cycle.
Manual
The earliest evolution of the firearm, there are many types of manual action firearms. These can be divided into two basic categories: single shot and repeating.
A single shot firearm can only be fired once per equipped barrel before it must be reloaded or charged via an external mechanism or series of steps. A repeating firearm can be fired multiple times, but can only be fired once with each subsequent pull of the trigger. Between trigger pulls, the firearm's action must be reloaded or charged via an internal mechanism.
Semi-automatic

A semi-automatic, self-loading, or "auto loader" firearm is one that performs all steps necessary to prepare it for firing again after a single discharge, until cartridges are no longer available in the weapon's feed device or magazine. Auto loaders fire on.e round with each pull of the trigger. Some people confuse the term with "fully automatic" firearms.  (See next.) While some semi-automatic rifles may resemble military-style firearms, they are not properly classified "Assault Weapons" which refers to those that continue to fire until the trigger is no longer depressed.
Automatic
An automatic firearm, or "fully automatic", "fully auto", or "full auto", is generally defined as one that continues to load and fire cartridges from its magazine as long as the trigger is depressed (and until the magazine is depleted of available ammunition. The first weapon generally considered in this category is the Gatling gun, originally a carriage-mounted, crank-operated firearm with multiple rotating barrels that was fielded in the American Civil War. The modern trigger-actuated machine gun began with various designs developed in the late 19th century and fielded in World War I, such as the Maxim gun, Lewis Gun, and MG 08 "Spandau". Most automatic weapons are classed as long guns (as the ammunition used is of similar type as for rifles, and the recoil of the weapon's rapid fire is better controlled with two hands), but handgun-sized automatic weapons also exist, generally in the "submachine gun" or "machine pistol" class.
Selective fire

Selective fire, or "select fire", means the capability of a weapon's fire control to be adjusted in either semi-automatic or fully automatic firing modes.  The modes are chosen by means of a selector, which varies depending on the weapon's design.  Some selective-fire weapons have burst fire mechanisms built in to limit the maximum number of shots fired in fully automatic mode, with most common limits being two or three rounds per trigger pull.  The presence of selective-fire modes on firearms allows more efficient use of ammunition for specific tactical needs, either precision-aimed or suppressive fire.  This capability is most commonly found on military weapons of the 20th and 21st centuries, most notably the assault rifles.
Health hazards

Assault by firearm resulted in 173,000 deaths, globally, in 2015, up from 128,000 deaths in 1990,[8][9] however this represents a drop in rate from 2.41/100,000 in 1990 to 2.35/100,000 in 2015, as world population has increased by more than two billion.[10] Additionally, there were 32,000 unintentional firearm global deaths in 2015.[8] In 2017, there were 39,773 gun-related deaths in the United States, and over 60% of suicides in the United States are from firearms.[11] Firearms are the second leading mechanism of injury deaths, after motor vehicle accidents.[12][13] To prevent unintentional injury, gun safety training includes education on proper firearm storage and firearm-handling etiquette.[14][15]
History

The first primitive firearms were invented about 1250 AD in China when the man-portable fire lance (a bamboo or metal tube that could shoot ignited gunpowder) was combined with projectiles such as scrap metal, broken porcelain, or darts/arrows.[5][16]
The earliest depiction of a firearm is a sculpture from a cave in Sichuan, China. The sculpture dates to the 12th century and is of a figure carrying a vase-shaped bombard, with flames and a cannonball coming out of it.[17]:31–32 The oldest surviving gun, a hand cannon made of bronze, has been dated to 1288 because it was discovered at a site in modern-day Acheng District, Heilongjiang, China, where the Yuan Shi records that battles were fought at that time.[18] The firearm had a 6.9 inch barrel of a 1-inch diameter, a 2.6 inch chamber for the gunpowder and a socket for the firearm's handle. It is 13.4 inches long and 7.8 pounds without the handle, which would have been made of wood.[17]:32
The Europeans and Arabs (first Mamluks) obtained firearms in the 14th century.[17]:1 The Koreans adopted firearms from the Chinese in the 14th century. The Turks, Iranians, (first Aq Qoyunlu and Safavids), and Indians (first Mughals) all got them no later than the 15th century. In each case directly or indirectly from the Europeans. The Japanese did not acquire firearms until the 16th century, and then from the Portuguese rather than the Chinese.[17]:31–32
The development behind firearms accelerated during the 19th and 20th centuries. Breech-loading became more or less a universal standard for the reloading of most hand-held firearms and continues to be so with some notable exceptions (such as mortars). Instead of loading individual rounds into weapons, magazines holding multiple munitions were adopted—these aided rapid reloading. Automatic and semi-automatic firing mechanisms meant that a single soldier could fire many more rounds in a minute than a vintage weapon could fire over the course of a battle. Polymers and alloys in firearm construction made weaponry progressively lighter and thus easier to deploy. Ammunition changed over the centuries from simple metallic ball-shaped projectiles that rattled down the barrel to bullets and cartridges manufactured to high precision. Especially in the past century has particular attention been devoted to accuracy and sighting to make firearms altogether far more accurate than ever before. More than any single factor though, firearms have proliferated due to the advent of mass production—enabling arms manufacturers to produce large quantities of weaponry to a consistent standard.
The force of a projectile is related to the kinetic energy imparted to it, given by the formula

E

k

=

1
2

m

v

2

{\displaystyle E_{\text{k}}={\tfrac {1}{2}}mv^{2}}

 where

m

{\displaystyle m}

 is the mass and

v

{\displaystyle v}

 is the velocity of the projectile.
Generally, kinetic energy can be enhanced in two ways:
By increasing the mass of the bullet, either by increasing caliber (and thus size and weight), or by using denser materials like uranium or tungsten.
By increasing the projectile's velocity, through better or larger propellant charges, through better manufacturing tolerances and materials in bullet and barrel, or through longer barrels.
Velocities of bullets increased with the use of a "jacket" of a metal such as copper or copper alloys that covered a lead core and allowed the bullet to glide down the barrel more easily than exposed lead. Such bullets are designated as "full metal jacket" (FMJ). Such FMJ bullets are less likely to fragment on impact and are more likely to traverse through a target while imparting less energy. Hence, FMJ bullets impart less tissue damage than non-jacketed bullets that expand. (Dougherty and Eidt, 2009) This led to their adoption for military use by countries adhering to the Hague Convention in 1899.
That said, the basic principle behind firearm operation remains unchanged to this day. A musket of several centuries ago is still similar in principle to a modern-day assault rifle—using the expansion of gases to propel projectiles over long distances—albeit less accurately and rapidly.[19]
Evolution
Early models
Fire lances

The Chinese fire lance was the direct predecessor to the modern concept of the firearm. It was not a gun itself, but an addition to the soldiers' spears. Originally it consisted of paper or bamboo barrels that would have incendiary gunpowder within it, that could be lit one time and would project flames at the enemy. Sometimes the Chinese troops would place small projectiles within the barrel that would also be projected when the gunpowder was lit, but most of the explosive force would create flames. Later, the barrel was changed to be made of metal, so that a more explosive gunpowder could be used and put more force into the propulsion of the projectile.[17]:31–32
Hand cannons

The original predecessor of all firearms, the Chinese fire lance and hand cannon were loaded with gunpowder and the shot (initially lead shot, later replaced by cast iron) through the muzzle, while a fuse was placed at the rear. This fuse was lit, causing the gunpowder to ignite and propel the cannonball. In military use, the standard hand cannon was tremendously powerful, while also being somewhat useless due to relative inability of the gunner to aim the weapon, or control the ballistic properties of the projectile. Recoil could be absorbed by bracing the barrel against the ground using a wooden support, the forerunner of the stock. Neither the quality or amount of gunpowder, nor the consistency in projectile dimensions were controlled, with resulting inaccuracy in firing due to windage, variance in gunpowder composition, and the difference in diameter between the bore and the shot. The hand cannons were replaced by lighter carriage-mounted artillery pieces, and ultimately the arquebus.
Muskets

Muzzle-loading muskets (smooth-bored long guns) were among the first firearms developed. The firearm was loaded through the muzzle with gunpowder, optionally some wadding and then a bullet (usually a solid lead ball, but musketeers could shoot stones when they ran out of bullets). Greatly improved muzzleloaders (usually rifled instead of smooth-bored) are manufactured today and have many enthusiasts, many of whom hunt large and small game with their guns. Muzzleloaders have to be manually reloaded after each shot; a skilled archer could fire multiple arrows faster than most early muskets could be reloaded and fired, although by the mid-18th century, when muzzleloaders became the standard small armament of the military, a well-drilled soldier could fire six rounds in a minute using prepared cartridges in his musket. Before then, effectiveness of muzzleloaders was hindered by both the low reloading speed and, before the firing mechanism was perfected, the very high risk posed by the firearm to the person attempting to fire it.
One interesting solution to the reloading problem was the "Roman Candle Gun" with superposed loads. This was a muzzleloader in which multiple charges and balls were loaded one on top of the other, with a small hole in each ball to allow the subsequent charge to be ignited after the one ahead of it was ignited. It was neither a very reliable nor popular firearm, but it enabled a form of "automatic" fire long before the advent of the machine gun.[20]
Loading techniques

Most early firearms were muzzle-loading. This form of loading has several disadvantages, such as a slow rate of fire and having to expose oneself to enemy fire to reload as the weapon had to be pointed upright so the powder could be poured through the muzzle into the breech followed by the ramming the projectile into the breech. As effective methods of sealing the breech were developed through the development of sturdy, weatherproof, self-contained metallic cartridges, muzzle-loaders were replaced by single-shot breech loaders. Eventually single-shot weapons were replaced by the following repeater type weapons.
Internal magazines

Many firearms made in the late 19th century through the 1950s used internal magazines to load the cartridge into the chamber of the weapon. The most notable and revolutionary weapons of this period appeared during the U.S. Civil War and they were the Spencer and Henry repeating rifles. Both used fixed tubular magazines, the former having the magazine in the buttstock and the latter under the barrel which allowed a larger capacity. Later weapons used fixed box magazines that could not be removed from the weapon without disassembling the weapon itself. Fixed magazines permitted the use of larger cartridges and eliminated the hazard of having the bullet of one cartridge butting next to the primer or rim of another cartridge. These magazines are loaded while they are in the weapon, often using a stripper clip. A clip is used to transfer cartridges into the magazine. Some notable weapons that use internal magazines include the Mosin–Nagant, the Mauser Kar 98k, the Springfield M1903, the M1 Garand, and the SKS. Firearms that have internal magazines are usually, but not always, rifles. Some exceptions to this include the Mauser C96 pistol, which uses an internal magazine, and the Breda 30, an Italian light machine gun.
Detachable magazines

Many modern firearms use what are called detachable or box magazines as their method of chambering a cartridge. Detachable magazines can be removed from the weapon without disassembling the firearms, usually by pushing the magazine release.
Belt-fed weapons

A belt or ammunition belt is a device used to retain and feed cartridges into a firearm commonly used on machine guns. Belts were originally composed of canvas or cloth with pockets spaced evenly to allow the belt to be mechanically fed into the gun. These designs were prone to malfunctions due to the effects of oil and other contaminants altering the belt. Later belt designs used permanently connected metal links to retain the cartridges during feeding. These belts were more tolerant to exposure to solvents and oil. Some notable weapons that use belts are the M240, the M249, the M134 Minigun, and the PK Machine Gun.
Firing mechanisms

Matchlock

Matchlocks were the first and simplest firearms firing mechanisms developed. Using the matchlock mechanism, the powder in the gun barrel was ignited by a piece of burning cord called a "match". The match was wedged into one end of an S-shaped piece of steel. As the trigger (often actually a lever) was pulled, the match was brought into the open end of a "touch hole" at the base of the gun barrel, which contained a very small quantity of gunpowder, igniting the main charge of gunpowder in the gun barrel. The match usually had to be relit after each firing. The main parts to the matchlock firing mechanism are the pan, match, arm and trigger.[21] A benefit of the pan and arm swivel being moved to the side of the gun was it gave a clear line of fire.[22] An advantage to the matchlock firing mechanism is that it did not misfire. However, it also came with some disadvantages. One disadvantage was if it was raining the match could not be kept lit to fire the weapon.  Another issue with the match was it could give away the position of soldiers because of the glow, sound, and smell.[23]
Wheellock

The wheellock action, a successor to the matchlock, predated the flintlock. Despite its many faults, the wheellock was a significant improvement over the matchlock in terms of both convenience and safety, since it eliminated the need to keep a smoldering match in proximity to loose gunpowder. It operated using a small wheel much like that on cigarette lighters which was wound up with a key before use and which, when the trigger was pulled, spun against a flint, creating the shower of sparks that ignited the powder in the touch hole. Supposedly invented by Leonardo da Vinci, the Italian Renaissance man, the wheellock action was an innovation that was not widely adopted due to the high cost of the clockwork mechanism.
Flintlock

The flintlock action was a major innovation in firearm design. The spark used to ignite the gunpowder in the touch hole was supplied by a sharpened piece of flint clamped in the jaws of a "cock" which, when released by the trigger, struck a piece of steel called the "frizzen" to create the necessary sparks. (The spring-loaded arm that holds a piece of flint or pyrite is referred to as a cock because of its resemblance to a rooster.) The cock had to be manually reset after each firing, and the flint had to be replaced periodically due to wear from striking the frizzen. (See also flintlock mechanism, snaphance, Miquelet lock) The flintlock was widely used during the 18th and 19th centuries in both muskets and rifles.

Percussion cap

Percussion caps (caplock mechanisms), coming into wide service in the 19th century, were a dramatic improvement over flintlocks. With the percussion cap mechanism, the small primer charge of gunpowder used in all preceding firearms was replaced by a completely self-contained explosive charge contained in a small brass "cap". The cap was fastened to the touch hole of the gun (extended to form a "nipple") and ignited by the impact of the gun's "hammer". (The hammer is roughly the same as the cock found on flintlocks except that it doesn't clamp onto anything.) In the case of percussion caps the hammer was hollow on the end to fit around the cap in order to keep the cap from fragmenting and injuring the shooter.
Once struck, the flame from the cap in turn ignited the main charge of gunpowder, as with the flintlock, but there was no longer any need to charge the touch hole with gunpowder, and even better, the touch hole was no longer exposed to the elements. As a result, the percussion cap mechanism was considerably safer, far more weatherproof, and vastly more reliable (cloth-bound cartridges containing a premeasured charge of gunpowder and a ball had been in regular military service for many years, but the exposed gunpowder in the entry to the touch hole had long been a source of misfires). All muzzleloaders manufactured since the second half of the 19th century use percussion caps except those built as replicas of the flintlock or earlier firearms.
Cartridges

A major innovation in firearms and light artillery came in the second half of the 19th century when ammunition, previously delivered as separate bullets and powder, was combined in a single metallic (usually brass) cartridge containing a percussion cap, powder, and a bullet in one weatherproof package. The main technical advantage of the brass cartridge case was the effective and reliable sealing of high pressure gasses at the breech, as the gas pressure forces the cartridge case to expand outward, pressing it firmly against the inside of the gun barrel chamber.  This prevents the leakage of hot gas which could injure the shooter. The brass cartridge also opened the way for modern repeating arms, by uniting the bullet, gunpowder and primer into one assembly that could be fed reliably into the breech by a mechanical action in the firearm.
Before this, a "cartridge" was simply a premeasured quantity of gunpowder together with a ball in a small cloth bag (or rolled paper cylinder), which also acted as wadding for the charge and ball. This early form of cartridge had to be rammed into the muzzleloader's barrel, and either a small charge of gunpowder in the touch hole or an external percussion cap mounted on the touch hole ignited the gunpowder in the cartridge. Cartridges with built-in percussion caps (called "primers") continue to this day to be the standard in firearms. In cartridge-firing firearms, a hammer (or a firing pin struck by the hammer) strikes the cartridge primer, which then ignites the gunpowder within. The primer charge is at the base of the cartridge, either within the rim (a "rimfire" cartridge) or in a small percussion cap embedded in the center of the base (a "centerfire" cartridge). As a rule, centerfire cartridges are more powerful than rimfire cartridges, operating at considerably higher pressures than rimfire cartridges. Centerfire cartridges are also safer, as a dropped rimfire cartridge has the potential to discharge if its rim strikes the ground with sufficient force to ignite the primer. This is practically impossible with most centerfire cartridges.
Nearly all contemporary firearms load cartridges directly into their breech. Some additionally or exclusively load from a magazine that holds multiple cartridges. A magazine is defined as a part of the firearm which exists to store ammunition and assist in its feeding by the action into the breech (such as through the rotation of a revolver's cylinder or by spring-loaded platforms in most pistol and rifle designs). Some magazines, such as that of most centerfire hunting rifles and all revolvers, are internal to and inseparable from the firearm, and are loaded by using a "clip".  A clip, often mistakingly used to refer to a detachable "magazine", is a device that holds the ammunition by the rim of the case and is designed to assist the shooter in reloading the firearm's magazine. Examples include revolver speedloaders, the stripper clip used to aid loading rifles such as the Lee–Enfield or Mauser 98, and the en-bloc clip used in loading the M1 Garand. In this sense, "magazines" and "clips", though often used synonymously, refer to different types of devices.
Repeating, semi-automatic, and automatic firearms

Many firearms are "single shot": i.e., each time a cartridge is fired, the operator must manually re-cock the firearm and load another cartridge. The classic single-barreled shotgun is a good example. A firearm that can load multiple cartridges as the firearm is re-cocked is considered a "repeating firearm" or simply a "repeater". A lever-action rifle, a pump-action shotgun, and most bolt-action rifles are good examples of repeating firearms. A firearm that automatically re-cocks and reloads the next round with each trigger pull is considered a semi-automatic or autoloading firearm.
The first "rapid firing" firearms were usually similar to the 19th century Gatling gun, which would fire cartridges from a magazine as fast as and as long as the operator turned a crank. Eventually, the "rapid" firing mechanism was perfected and miniaturized to the extent that either the recoil of the firearm or the gas pressure from firing could be used to operate it, thus the operator needed only to pull a trigger (which made the firing mechanisms truly "automatic"). An automatic (or "fully automatic") firearm is one that automatically re-cocks, reloads, and fires as long as the trigger is depressed. An automatic firearm is capable of firing multiple rounds with one pull of the trigger. The Gatling gun may have been the first automatic weapon, though the modern trigger-actuated machine gun was not widely introduced until the First World War with the German "Spandau" and British Lewis Gun. Automatic rifles such as the Browning Automatic Rifle were in common use by the military during the early part of the 20th century, and automatic rifles that fired handgun rounds, known as submachine guns, also appeared in this time. Many modern military firearms have a selective fire option, which is a mechanical switch that allows the firearm be fired either in the semi-automatic or fully automatic mode. In the current M16A2 and M16A4 variants of the U.S.-made M16, continuous fully automatic fire is not possible, having been replaced by an automatic burst of three cartridges (this conserves ammunition and increases controllability). Automatic weapons are largely restricted to military and paramilitary organizations, though many automatic designs are infamous for their use by civilians.
See also

Firearm science and technology
Ballistics (Internal ballistics, Transitional ballistics, External ballistics, Terminal ballistics)
Electrothermal-chemical technology
Firearm action
Glossary of firearms terms
Gunsmith
Physics of firearms
Vertical forward grip
Firearms and society
Celebratory gunfire
Firearms law and Gun politics
Firearms ownership
Gun control, Small arms trade and Right to keep and bear arms
Gun culture
Gun safety
Gun violence
Index of gun politics articles
Open carry and Concealed carry
Overview of gun laws by nation
Saturday night special
Shooting range
Shooting sport
List of firearms
List of firearm brands
List of aircraft weapons
List of battle rifles
List of pistols
List of shotguns
List of sniper rifles
List of submachine guns
List of infantry weapons of World War I
List of World War II firearms
List of common World War II infantry weapons
List of secondary and special-issue World War II infantry weapons
List of weapons of military aircraft of Germany during World War II
Firearms groups around the world
Association of Firearm Instructors
Dominion of Canada Rifle Association
National Rifle Association
National Rifle Association of the United Kingdom
PROGUN (Philippines)
Shooters and Fishers Party
Sporting Shooters Association of Australia

Sources


"'Coacervation"' is a unique type of electrostatically driven liquid-liquid phase separation, resulting from association of oppositely charged macro-ions. The term "coacervate" is sometimes used to refer to spherical aggregates of colloidal droplets held together by hydrophobic forces.[1] Coacervate droplets can measure from 1 to 100 micrometres across, while their soluble precursors[2][3] are typically on the order of less than 200nm.[4] The name "coacervate" derives from the Latin coacervare, meaning "to assemble together or cluster".
The process of coacervation[5] was famously proposed by Alexander Oparin and J. B. S. Haldane as crucial in his early theory of abiogenesis (origin of life/proiskhozhdenie zhizni). This theory proposes that metabolism predated information replication, although the discussion as to whether metabolism or molecules capable of template replication came first in the origins of life remains open[6] and for decades the theory of Oparin and Haldane was the leading approach to the origin of life question.
History
These structures were first investigated by the Dutch chemist H.G. Bungenberg de Jong, in 1932. A wide variety of solutions can give rise to them; for example, coacervates form spontaneously when a disordered polypeptide, such as gelatin, reacts with another biologically derived polyelectrolyte, such as gum arabic. They are interesting not only in that they provide a locally segregated environment, but also in that their boundaries allow the selective absorption of simple organic molecules from the surrounding medium. For example, a mix of carbohydrate solution with a protein solution, will favor the spontaneous formation of amoeba-like coacervates which change shape, merge, divide, form "vacuoles", release "vacuole contents", and show other lifelike properties.[7] In Oparin's view this amounts to an elementary form of metabolism. British scientist Bernal commented that they are "the nearest we can come to cells without introducing any biological – or, at any rate, any living biological – substance." However, the lack of any mechanism by which coacervates can reproduce leaves them far short of being living systems.[8]
Complex coacervation
Complex coacervation commonly refers to the liquid-liquid phase separation that results when solutions of two oppositely charged macroions are mixed, resulting in the formation of a dense macroion-rich phase, the precursors of which are soluble complexes.[9][10][11]
See also
Jeewanu
Microsphere
Protocell
Vesicle (biology and chemistry)


A battleship is a large armored warship with a main battery consisting of large caliber guns. During the late 19th and early 20th centuries the battleship was the most powerful type of warship, and a fleet of battleships was considered vital for any nation that desired to maintain command of the sea.
The term battleship came into formal use in the late 1880s to describe a type of ironclad warship,[1] now referred to by historians as pre-dreadnought battleships. In 1906, the commissioning of HMSDreadnought into the United Kingdom's Royal Navy heralded a revolution in battleship design. Subsequent battleship designs, influenced by HMS Dreadnought, were referred to as "dreadnoughts", though the term eventually became obsolete as they became the only type of battleship in common use.
Battleships were a symbol of naval dominance and national might, and for decades the battleship was a major factor in both diplomacy and military strategy.[2] A global arms race in battleship construction began in Europe in the 1890s and culminated at the decisive Battle of Tsushima in 1905,[3][4][5] the outcome of which significantly influenced the design of HMS Dreadnought.[6][7]  The launch of Dreadnought in 1906 commenced a new naval arms race. Three major fleet actions between steel battleships took place: the decisive battles of the Yellow Sea (1904) and Tsushima (1905) during the Russo-Japanese War, and the inconclusive Battle of Jutland (1916) during the First World War. Jutland was the largest naval battle and the only full-scale clash of battleships in the war, and it was the last major battle fought primarily by battleships in world history.[8]
The Naval Treaties of the 1920s and 1930s limited the number of battleships, though technical innovation in battleship design continued. Both the Allied and Axis powers built battleships during World War II, though the increasing importance of the aircraft carrier meant that the battleship played a less important role than had been expected.
The value of the battleship has been questioned, even during their heyday.[9] There were few of the decisive fleet battles that battleship proponents expected, and used to justify the vast resources spent on building battlefleets. Even in spite of their huge firepower and protection, battleships were increasingly vulnerable to much smaller and relatively inexpensive weapons: initially the torpedo and the naval mine, and later aircraft and the guided missile.[10] The growing range of naval engagements led to the aircraft carrier replacing the battleship as the leading capital ship during World War II, with the last battleship to be launched being HMSVanguard in 1944. Four battleships were retained by the United States Navy until the end of the Cold War for fire support purposes and were last used in combat during the Gulf War in 1991. The last battleships were stricken from the U.S. Naval Vessel Register in the 2000s.
History of battleships
Ships of the line

A ship of the line was the dominant warship of its age. It was a large, unarmored wooden sailing ship which mounted a battery of up to 120 smoothbore guns and carronades. The ship of the line developed gradually over centuries and, apart from growing in size, it changed little between the adoption of line of battle tactics in the early 17th century and the end of the sailing battleship's heyday in the 1830s. From 1794, the alternative term 'line of battle ship' was contracted (informally at first) to 'battle ship' or 'battleship'.[11]
The sheer number of guns fired broadside meant a ship of the line could wreck any wooden enemy, holing her hull, knocking down masts, wrecking her rigging, and killing her crew. However, the effective range of the guns was as little as a few hundred yards, so the battle tactics of sailing ships depended in part on the wind.
The first major change to the ship of the line concept was the introduction of steam power as an auxiliary propulsion system. Steam power was gradually introduced to the navy in the first half of the 19th century, initially for small craft and later for frigates. The French Navy introduced steam to the line of battle with the 90-gun Napoléon in 1850[12]—the first true steam battleship.[13] Napoléon was armed as a conventional ship-of-the-line, but her steam engines could give her a speed of 12 knots (22km/h), regardless of the wind condition. This was a potentially decisive advantage in a naval engagement. The introduction of steam accelerated the growth in size of battleships. France and the United Kingdom were the only countries to develop fleets of wooden steam screw battleships although several other navies operated small numbers of screw battleships, including Russia (9), the Ottoman Empire (3), Sweden (2), Naples (1), Denmark (1) and Austria (1).[14][2]
Ironclads

The adoption of steam power was only one of a number of technological advances which revolutionized warship design in the 19th century. The ship of the line was overtaken by the ironclad: powered by steam, protected by metal armor, and armed with guns firing high-explosive shells.
Explosive shells
Guns that fired explosive or incendiary shells were a major threat to wooden ships, and these weapons quickly became widespread after the introduction of 8-inch shell guns as part of the standard armament of French and American line-of-battle ships in 1841.[15] In the Crimean War, six line-of-battle ships and two frigates of the Russian Black Sea Fleet destroyed seven Turkish frigates and three corvettes with explosive shells at the Battle of Sinop in 1853.[16] Later in the war, French ironclad floating batteries used similar weapons against the defenses at the Battle of Kinburn.[17]
Nevertheless, wooden-hulled ships stood up comparatively well to shells, as shown in the 1866 Battle of Lissa, where the modern Austrian steam two-decker SMSKaiser ranged across a confused battlefield, rammed an Italian ironclad and took 80 hits from Italian ironclads,[18] many of which were shells,[19] but including at least one 300-pound shot at point-blank range. Despite losing her bowsprit and her foremast, and being set on fire, she was ready for action again the very next day.[20]
Iron armor and construction

The development of high-explosive shells made the use of iron armor plate on warships necessary. In 1859 France launched Gloire, the first ocean-going ironclad warship. She had the profile of a ship of the line, cut to one deck due to weight considerations. Although made of wood and reliant on sail for most journeys, Gloire was fitted with a propeller, and her wooden hull was protected by a layer of thick iron armor.[21] Gloire prompted further innovation from the Royal Navy, anxious to prevent France from gaining a technological lead.
The superior armored frigate Warrior followed Gloire by only 14 months, and both nations embarked on a program of building new ironclads and converting existing screw ships of the line to armored frigates.[22] Within two years, Italy, Austria, Spain and Russia had all ordered ironclad warships, and by the time of the famous clash of the USSMonitor and the CSSVirginia at the Battle of Hampton Roads at least eight navies possessed ironclad ships.[2]

Navies experimented with the positioning of guns, in turrets (like the USS Monitor), central-batteries or barbettes, or with the ram as the principal weapon. As steam technology developed, masts were gradually removed from battleship designs. By the mid-1870s steel was used as a construction material alongside iron and wood. The French Navy's Redoutable, laid down in 1873 and launched in 1876, was a central battery and barbette warship which became the first battleship in the world to use steel as the principal building material.[24]
Pre-dreadnought battleship

The term "battleship" was officially adopted by the Royal Navy in the re-classification of 1892. By the 1890s, there was an increasing similarity between battleship designs, and the type that later became known as the 'pre-dreadnought battleship' emerged. These were heavily armored ships, mounting a mixed battery of guns in turrets, and without sails. The typical first-class battleship of the pre-dreadnought era displaced 15,000 to 17,000tons, had a speed of 16 knots (30km/h), and an armament of four 12-inch (305mm) guns in two turrets fore and aft with a mixed-caliber secondary battery amidships around the superstructure.[1] An early design with superficial similarity to the pre-dreadnought is the British Devastationclass of 1871.[25][26]
The slow-firing 12-inch (305mm) main guns were the principal weapons for battleship-to-battleship combat. The intermediate and secondary batteries had two roles. Against major ships, it was thought a 'hail of fire' from quick-firing secondary weapons could distract enemy gun crews by inflicting damage to the superstructure, and they would be more effective against smaller ships such as cruisers. Smaller guns (12-pounders and smaller) were reserved for protecting the battleship against the threat of torpedo attack from destroyers and torpedo boats.[27]
The beginning of the pre-dreadnought era coincided with Britain reasserting her naval dominance. For many years previously, Britain had taken naval supremacy for granted. Expensive naval projects were criticised by political leaders of all inclinations.[2] However, in 1888 a war scare with France and the build-up of the Russian navy gave added impetus to naval construction, and the British Naval Defence Act of 1889 laid down a new fleet including eight new battleships. The principle that Britain's navy should be more powerful than the two next most powerful fleets combined was established. This policy was designed to deter France and Russia from building more battleships, but both nations nevertheless expanded their fleets with more and better pre-dreadnoughts in the 1890s.[2]

In the last years of the 19th century and the first years of the 20th, the escalation in the building of battleships became an arms race between Britain and Germany. The German naval laws of 1890 and 1898 authorised a fleet of 38 battleships, a vital threat to the balance of naval power.[2] Britain answered with further shipbuilding, but by the end of the pre-dreadnought era, British supremacy at sea had markedly weakened. In 1883, the United Kingdom had 38 battleships, twice as many as France and almost as many as the rest of the world put together. By 1897, Britain's lead was far smaller due to competition from France, Germany, and Russia, as well as the development of pre-dreadnought fleets in Italy, the United States and Japan.[28] The Ottoman Empire, Spain, Sweden, Denmark, Norway, the Netherlands, Chile and Brazil all had second-rate fleets led by armored cruisers, coastal defence ships or monitors.[29]
Pre-dreadnoughts continued the technical innovations of the ironclad. Turrets, armor plate, and steam engines were all improved over the years, and torpedo tubes were also introduced. A small number of designs, including the American Kearsarge and Virginiaclasses, experimented with all or part of the 8-inch intermediate battery superimposed over the 12-inch primary. Results were poor: recoil factors and blast effects resulted in the 8-inch battery being completely unusable, and the inability to train the primary and intermediate armaments on different targets led to significant tactical limitations. Even though such innovative designs saved weight (a key reason for their inception), they proved too cumbersome in practice.[30]
Dreadnought era

In 1906, the British Royal Navy launched the revolutionary HMSDreadnought. Created as a result of pressure from Admiral Sir John ("Jackie") Fisher, HMS Dreadnought made existing battleships obsolete. Combining an "all-big-gun" armament of ten 12-inch (305mm) guns with unprecedented speed (from steam turbine engines) and protection, she prompted navies worldwide to re-evaluate their battleship building programs. While the Japanese had laid down an all-big-gun battleship, Satsuma, in 1904[31] and the concept of an all-big-gun ship had been in circulation for several years, it had yet to be validated in combat. Dreadnought sparked a new arms race, principally between Britain and Germany but reflected worldwide, as the new class of warships became a crucial element of national power.[32]
Technical development continued rapidly through the dreadnought era, with steep changes in armament, armor and propulsion. Ten years after Dreadnought's commissioning, much more powerful ships, the super-dreadnoughts, were being built.
Origin

In the first years of the 20th century, several navies worldwide experimented with the idea of a new type of battleship with a uniform armament of very heavy guns.
Admiral Vittorio Cuniberti, the Italian Navy's chief naval architect, articulated the concept of an all-big-gun battleship in 1903. When the Regia Marina did not pursue his ideas, Cuniberti wrote an article in Jane's proposing an "ideal" future British battleship, a large armored warship of 17,000tons, armed solely with a single calibre main battery (twelve 12-inch [305mm] guns), carrying 300-millimetre (12in) belt armor, and capable of 24 knots (44km/h).[33]
The Russo-Japanese War provided operational experience to validate the "all-big-gun" concept. At the Yellow Sea and Tsushima, pre-dreadnoughts exchanged volleys at ranges of 7,600–12,000 yd (7 to 11km), beyond the range of the secondary batteries. It is often held that these engagements demonstrated the importance of the 12-inch (305mm) gun over its smaller counterparts, though some historians take the view that secondary batteries were just as important as the larger weapons.[2]
In Japan, the two battleships of the 1903–04 Programme were the first to be laid down as all-big-gun designs, with eight 12-inch guns. However, the design had armor which was considered too thin, demanding a substantial redesign.[34] The financial pressures of the Russo-Japanese War and the short supply of 12-inch guns which had to be imported from Britain meant these ships were completed with a mixed 10- and 12-inch armament. The 1903–04 design also retained traditional triple-expansion steam engines.[35]

As early as 1904, Jackie Fisher had been convinced of the need for fast, powerful ships with an all-big-gun armament. If Tsushima influenced his thinking, it was to persuade him of the need to standardise on 12-inch (305mm) guns.[2] Fisher's concerns were submarines and destroyers equipped with torpedoes, then threatening to outrange battleship guns, making speed imperative for capital ships.[2] Fisher's preferred option was his brainchild, the battlecruiser: lightly armored but heavily armed with eight 12-inch guns and propelled to 25 knots (46km/h) by steam turbines.[36]
It was to prove this revolutionary technology that Dreadnought was designed in January 1905, laid down in October 1905 and sped to completion by 1906. She carried ten 12-inch guns, had an 11-inch armor belt, and was the first large ship powered by turbines. She mounted her guns in five turrets; three on the centerline (one forward, two aft) and two on the wings, giving her at her launch twice the broadside of any other warship. She retained a number of 12-pound (3-inch, 76mm) quick-firing guns for use against destroyers and torpedo-boats. Her armor was heavy enough for her to go head-to-head with any other ship in a gun battle, and conceivably win.[37]

Dreadnought was to have been followed by three Invincible-class battlecruisers, their construction delayed to allow lessons from Dreadnought to be used in their design. While Fisher may have intended Dreadnought to be the last Royal Navy battleship,[2] the design was so successful he found little support for his plan to switch to a battlecruiser navy. Although there were some problems with the ship (the wing turrets had limited arcs of fire and strained the hull when firing a full broadside, and the top of the thickest armor belt lay below the waterline at full load), the Royal Navy promptly commissioned another six ships to a similar design in the Bellerophon and St. Vincentclasses.
An American design, South Carolina, authorized in 1905 and laid down in December 1906, was another of the first dreadnoughts, but she and her sister, Michigan, were not launched until 1908. Both used triple-expansion engines and had a superior layout of the main battery, dispensing with Dreadnought's wing turrets. They thus retained the same broadside, despite having two fewer guns.
Arms race

In 1897, before the revolution in design brought about by HMS Dreadnought, the Royal Navy had 62 battleships in commission or building, a lead of 26 over France and 50 over Germany.[28] In 1906, the Royal Navy owned the field with Dreadnought. The new class of ship prompted an arms race with major strategic consequences. Major naval powers raced to build their own dreadnoughts. Possession of modern battleships was not only seen as vital to naval power, but also, as with nuclear weapons after WWII, represented a nation's standing in the world.[2] Germany, France, Japan,[38] Italy, Austria, and the United States all began dreadnought programmes; while Ottoman Turkey, Argentina, Russia,[38] Brazil, and Chile commissioned dreadnoughts to be built in British and American yards.
World War I

The battleship, particularly the dreadnought, was the dominant naval weapon of the World War I era. There were few serious challenges at that time. The most significant naval battles of World War I, such as Jutland (May 31, 1916 – June 1, 1916), were fought by battleships and their battlecruiser cousins.[39]

By virtue of geography, the Royal Navy was able to use her imposing battleship and battlecruiser fleet to impose a strict and successful naval blockade of Germany and kept Germany's smaller battleship fleet bottled up in the North Sea: only narrow channels led to the Atlantic Ocean and these were guarded by British forces.[40] Both sides were aware that, because of the greater number of British dreadnoughts, a full fleet engagement would be likely to result in a British victory. The German strategy was therefore to try to provoke an engagement on their terms: either to induce a part of the Grand Fleet to enter battle alone, or to fight a pitched battle near the German coastline, where friendly minefields, torpedo-boats and submarines could be used to even the odds.[41] This did not happen however, due in large part to the necessity to keep submarines for the Atlantic campaign. Submarines were the only vessels in the Imperial German Navy able to break out and raid British commerce in force, but even though they sank many merchant ships, they could not successfully counter-blockade the United Kingdom; the Royal Navy successfully adopted convoy tactics to combat Germany's submarine counter-blockade and eventually defeated it.[39] This was in stark contrast to Britain's successful battleship blockade of Germany, which was a major cause of Germany's economic collapse in 1918.

The first two years of war saw the Royal Navy's battleships and battlecruisers regularly "sweep" the North Sea making sure that no German ships could get in or out. Only a few German surface ships that were already at sea, such as the famous light cruiser SMSEmden, were able to raid commerce. Even some of those that did manage to get out were hunted down by battlecruisers, as in the Battle of the Falklands, December 7, 1914. The results of sweeping actions in the North Sea were battles such as the Heligoland Bight and Dogger Bank and German raids on the English coast, all of which were attempts by the Germans to lure out portions of the Grand Fleet in an attempt to defeat the Royal Navy in detail. On May 31, 1916, a further attempt to draw British ships into battle on German terms resulted in a clash of the battlefleets in the Battle of Jutland.[42] The German fleet withdrew to port after two short encounters with the British fleet. Less than two months later, the Germans once again attempted to draw portions of the Grand Fleet into battle. The resulting Action of 19 August 1916 proved inconclusive. This reinforced German determination not to engage in a fleet to fleet battle.[43]

In the other naval theatres there were no decisive pitched battles. In the Black Sea, engagement between Russian and Ottoman battleships was restricted to skirmishes. In the Baltic Sea, action was largely limited to the raiding of convoys, and the laying of defensive minefields; the only significant clash of battleship squadrons there was the Battle of Moon Sound at which one Russian pre-dreadnought was lost. The Adriatic was in a sense the mirror of the North Sea: the Austro-Hungarian dreadnought fleet remained bottled up by the British and French blockade. And in the Mediterranean, the most important use of battleships was in support of the amphibious assault on Gallipoli.[44]
In September 1914, the threat posed to surface ships by German U-boats was confirmed by successful attacks on British cruisers, including the sinking of three British armored cruisers by the German submarine SMU-9 in less than an hour. The British Super-dreadnought HMSAudacious soon followed suit as she struck a mine laid by a German U-boat in October 1914 and sank. The threat that German U-boats posed to British dreadnoughts was enough to cause the Royal Navy to change their strategy and tactics in the North Sea to reduce the risk of U-boat attack.[45] Further near-misses from submarine attacks on battleships and casualties amongst cruisers led to growing concern in the Royal Navy about the vulnerability of battleships.
As the war wore on however, it turned out that whilst submarines did prove to be a very dangerous threat to older pre-dreadnought battleships, as shown by examples such as the sinking of Mesûdiye, which was caught in the Dardanelles by a British submarine[46] and HMSMajestic and HMSTriumph were torpedoed by U-21 as well as HMSFormidable, HMSCornwallis, HMSBritannia etc., the threat posed to dreadnought battleships proved to have been largely a false alarm. HMS Audacious turned out to be the only dreadnought sunk by a submarine in World War I.[39] While battleships were never intended for anti-submarine warfare, there was one instance of a submarine being sunk by a dreadnought battleship. HMS Dreadnought rammed and sank the German submarine U-29 on March 18, 1915 off Moray Firth.[39]

Whilst the escape of the German fleet from the superior British firepower at Jutland was effected by the German cruisers and destroyers successfully turning away the British battleships, the German attempt to rely on U-boat attacks on the British fleet failed.[47]
Torpedo boats did have some successes against battleships in World War I, as demonstrated by the sinking of the British pre-dreadnought HMSGoliath by Muâvenet-i Millîye during the Dardanelles Campaign and the destruction of the Austro-Hungarian dreadnought SMSSzent István by Italian motor torpedo boats in June 1918. In large fleet actions, however, destroyers and torpedo boats were usually unable to get close enough to the battleships to damage them. The only battleship sunk in a fleet action by either torpedo boats or destroyers was the obsolescent German pre-dreadnought SMSPommern. She was sunk by destroyers during the night phase of the Battle of Jutland.
The German High Seas Fleet, for their part, were determined not to engage the British without the assistance of submarines; and since the submarines were needed more for raiding commercial traffic, the fleet stayed in port for much of the war.[48]
Inter-war period
For many years, Germany simply had no battleships. The Armistice with Germany required that most of the High Seas Fleet be disarmed and interned in a neutral port; largely because no neutral port could be found, the ships remained in British custody in Scapa Flow, Scotland. The Treaty of Versailles specified that the ships should be handed over to the British. Instead, most of them were scuttled by their German crews on June 21, 1919 just before the signature of the peace treaty. The treaty also limited the German Navy, and prevented Germany from building or possessing any capital ships.[49]

The inter-war period saw the battleship subjected to strict international limitations to prevent a costly arms race breaking out.[50]

While the victors were not limited by the Treaty of Versailles, many of the major naval powers were crippled after the war. Faced with the prospect of a naval arms race against the United Kingdom and Japan, which would in turn have led to a possible Pacific war, the United States was keen to conclude the Washington Naval Treaty of 1922. This treaty limited the number and size of battleships that each major nation could possess, and required Britain to accept parity with the U.S. and to abandon the British alliance with Japan.[51] The Washington treaty was followed by a series of other naval treaties, including the First Geneva Naval Conference (1927), the First London Naval Treaty (1930), the Second Geneva Naval Conference (1932), and finally the Second London Naval Treaty (1936), which all set limits on major warships. These treaties became effectively obsolete on September 1, 1939 at the beginning of World War II, but the ship classifications that had been agreed upon still apply.[52] The treaty limitations meant that fewer new battleships were launched in 1919–1939 than in 1905–1914. The treaties also inhibited development by imposing upper limits on the weights of ships. Designs like the projected British N3-class battleship, the first American South Dakotaclass, and the Japanese Kiiclass—all of which continued the trend to larger ships with bigger guns and thicker armor—never got off the drawing board. Those designs which were commissioned during this period were referred to as treaty battleships.[53]
Rise of air power

As early as 1914, the British Admiral Percy Scott predicted that battleships would soon be made irrelevant by aircraft.[54] By the end of World War I, aircraft had successfully adopted the torpedo as a weapon.[55] In 1921 the Italian general and air theorist Giulio Douhet completed a hugely influential treatise on strategic bombing titled The Command of the Air, which foresaw the dominance of air power over naval units.
In the 1920s, General Billy Mitchell of the United States Army Air Corps, believing that air forces had rendered navies around the world obsolete, testified in front of Congress that "1,000 bombardment airplanes can be built and operated for about the price of one battleship" and that a squadron of these bombers could sink a battleship, making for more efficient use of government funds.[56] This infuriated the U.S. Navy, but Mitchell was nevertheless allowed to conduct a careful series of bombing tests alongside Navy and Marine bombers. In 1921, he bombed and sank numerous ships, including the "unsinkable" German World War I battleship SMSOstfriesland and the American pre-dreadnought Alabama.[57]
Although Mitchell had required "war-time conditions", the ships sunk were obsolete, stationary, defenseless and had no damage control. The sinking of Ostfriesland was accomplished by violating an agreement that would have allowed Navy engineers to examine the effects of various munitions: Mitchell's airmen disregarded the rules, and sank the ship within minutes in a coordinated attack. The stunt made headlines, and Mitchell declared, "No surface vessels can exist wherever air forces acting from land bases are able to attack them." While far from conclusive, Mitchell's test was significant because it put proponents of the battleship against naval aviation on the back foot.[2] Rear Admiral William A. Moffett used public relations against Mitchell to make headway toward expansion of the U.S. Navy's nascent aircraft carrier program.[58]
Rearmament
The Royal Navy, United States Navy, and Imperial Japanese Navy extensively upgraded and modernized their World War I–era battleships during the 1930s. Among the new features were an increased tower height and stability for the optical rangefinder equipment (for gunnery control), more armor (especially around turrets) to protect against plunging fire and aerial bombing, and additional anti-aircraft weapons. Some British ships received a large block superstructure nicknamed the "Queen Anne's castle", such as in Queen Elizabeth and Warspite, which would be used in the new conning towers of the King George V-class fast battleships. External bulges were added to improve both buoyancy to counteract weight increase and provide underwater protection against mines and torpedoes. The Japanese rebuilt all of their battleships, plus their battlecruisers, with distinctive "pagoda" structures, though the Hiei received a more modern bridge tower that would influence the new Yamatoclass. Bulges were fitted, including steel tube arrays to improve both underwater and vertical protection along the waterline. The U.S. experimented with cage masts and later tripod masts, though after the Japanese attack on Pearl Harbor some of the most severely damaged ships (such as West Virginia and California) were rebuilt with tower masts, for an appearance similar to their Iowa-class contemporaries. Radar, which was effective beyond visual range and effective in complete darkness or adverse weather, was introduced to supplement optical fire control.[59]
Even when war threatened again in the late 1930s, battleship construction did not regain the level of importance it had held in the years before World War I. The "building holiday" imposed by the naval treaties meant the capacity of dockyards worldwide had shrunk, and the strategic position had changed.[60]
In Germany, the ambitious Plan Z for naval rearmament was abandoned in favor of a strategy of submarine warfare supplemented by the use of battlecruisers and commerce raiding (in particular by Bismarck-class battleships). In Britain, the most pressing need was for air defenses and convoy escorts to safeguard the civilian population from bombing or starvation, and re-armament construction plans consisted of five ships of the King George Vclass. It was in the Mediterranean that navies remained most committed to battleship warfare. France intended to build six battleships of the Dunkerque and Richelieuclasses, and the Italians four Littorio-class ships. Neither navy built significant aircraft carriers. The U.S. preferred to spend limited funds on aircraft carriers until the South Dakotaclass. Japan, also prioritising aircraft carriers, nevertheless began work on three mammoth Yamatos (although the third, Shinano, was later completed as a carrier) and a planned fourth was cancelled.[10]
At the outbreak of the Spanish Civil War, the Spanish navy included only two small dreadnought battleships, España and Jaime I. España (originally named Alfonso XIII), by then in reserve at the northwestern naval base of El Ferrol, fell into Nationalist hands in July 1936. The crew aboard Jaime I remained loyal to the Republic, killed their officers, who apparently supported Franco's attempted coup, and joined the Republican Navy. Thus each side had one battleship; however, the Republican Navy generally lacked experienced officers. The Spanish battleships mainly restricted themselves to mutual blockades, convoy escort duties, and shore bombardment, rarely in direct fighting against other surface units.[61] In April 1937, España ran into a mine laid by friendly forces, and sank with little loss of life. In May 1937, Jaime I was damaged by Nationalist air attacks and a grounding incident. The ship was forced to go back to port to be repaired. There she was again hit by several aerial bombs. It was then decided to tow the battleship to a more secure port, but during the transport she suffered an internal explosion that caused 300 deaths and her total loss. Several Italian and German capital ships participated in the non-intervention blockade. On May 29, 1937, two Republican aircraft managed to bomb the German pocket battleship Deutschland outside Ibiza, causing severe damage and loss of life. Admiral Scheer retaliated two days later by bombarding Almería, causing much destruction, and the resulting Deutschland incident meant the end of German and Italian participation in non-intervention.[62]
World War II

The German battleshipSchleswig-Holstein—an obsolete pre-dreadnought—fired the first shots of World War II with the bombardment of the Polish garrison at Westerplatte;[63] and the final surrender of the Japanese Empire took place aboard a United States Navy battleship, USSMissouri. Between those two events, it had become clear that aircraft carriers were the new principal ships of the fleet and that battleships now performed a secondary role.
Battleships played a part in major engagements in Atlantic, Pacific and Mediterranean theaters; in the Atlantic, the Germans used their battleships as independent commerce raiders. However, clashes between battleships were of little strategic importance. The Battle of the Atlantic was fought between destroyers and submarines, and most of the decisive fleet clashes of the Pacific war were determined by aircraft carriers.
In the first year of the war, armored warships defied predictions that aircraft would dominate naval warfare. Scharnhorst and Gneisenau surprised and sank the aircraft carrier Glorious off western Norway in June 1940.[64] This engagement marked the only time a fleet carrier was sunk by surface gunnery. In the attack on Mers-el-Kébir, British battleships opened fire on the French battleships in the harbor near Oran in Algeria with their heavy guns, and later pursued fleeing French ships with planes from aircraft carriers.
The subsequent years of the war saw many demonstrations of the maturity of the aircraft carrier as a strategic naval weapon and its potential against battleships. The British air attack on the Italian naval base at Taranto sank one Italian battleship and damaged two more. The same Swordfish torpedo bombers played a crucial role in sinking the German battleship Bismarck.

On December 7, 1941, the Japanese launched a surprise attack on Pearl Harbor. Within a short time, five of eight U.S. battleships were sunk or sinking, with the rest damaged. All three American aircraft carriers were out to sea, however, and evaded destruction. The sinking of the British battleship Prince of Wales and battlecruiser Repulse, demonstrated the vulnerability of a battleship to air attack while at sea without sufficient air cover, settling the argument begun by Mitchell in 1921. Both warships were under way and en route to attack the Japanese amphibious force that had invaded Malaya when they were caught by Japanese land-based bombers and torpedo bombers on December 10, 1941.[65]
At many of the early crucial battles of the Pacific, for instance Coral Sea and Midway, battleships were either absent or overshadowed as carriers launched wave after wave of planes into the attack at a range of hundreds of miles. In later battles in the Pacific, battleships primarily performed shore bombardment in support of amphibious landings and provided anti-aircraft defense as escort for the carriers. Even the largest battleships ever constructed, Japan's Yamatoclass, which carried a main battery of nine 18-inch (46cm) guns and were designed as a principal strategic weapon, were never given a chance to show their potential in the decisive battleship action that figured in Japanese pre-war planning.[66]
The last battleship confrontation in history was the Battle of Surigao Strait, on October 25, 1944, in which a numerically and technically superior American battleship group destroyed a lesser Japanese battleship group by gunfire after it had already been devastated by destroyer torpedo attacks. All but one of the American battleships in this confrontation had previously been sunk during the attack on Pearl Harbor and subsequently raised and repaired. When Mississippi fired the last salvo of this battle, the last salvo fired by a battleship against another heavy ship, she was "firing a funeral salute to a finished era of naval warfare".[67] In April 1945, during the battle for Okinawa, the world's most powerful battleship,[68] the Yamato, was sent out on a suicide mission against a massive U.S. force and sunk by overwhelming pressure from carrier aircraft with nearly all hands lost.
Cold War

After World War II, several navies retained their existing battleships, but they were no longer strategically dominant military assets. Indeed, it soon became apparent that they were no longer worth the considerable cost of construction and maintenance and only one new battleship was commissioned after the war, HMSVanguard. During the war it had been demonstrated that battleship-on-battleship engagements like Leyte Gulf or the sinking of HMSHood were the exception and not the rule, and with the growing role of aircraft engagement ranges were becoming longer and longer, making heavy gun armament irrelevant. The armor of a battleship was equally irrelevant in the face of a nuclear attack as tactical missiles with a range of 100 kilometres (60mi) or more could be mounted on the Soviet Kildin-class destroyer and Whiskey-class submarines. By the end of the 1950s, smaller vessel classes such as destroyers, which formerly offered no noteworthy opposition to battleships, now were capable of eliminating battleships from outside the range of the ship's heavy guns.
The remaining battleships met a variety of ends. USSArkansas and Nagato were sunk during the testing of nuclear weapons in Operation Crossroads in 1946. Both battleships proved resistant to nuclear air burst but vulnerable to underwater nuclear explosions.[69] The Italian battleshipGiulio Cesare was taken by the Soviets as reparations and renamed Novorossiysk; she was sunk by a leftover German mine in the Black Sea on October 29, 1955. The two Andrea Doria-class ships were scrapped in 1956.[70] The French Lorraine was scrapped in 1954, Richelieu in 1968,[71] and Jean Bart in 1970.[72]
The United Kingdom's four surviving King George V-class ships were scrapped in 1957,[73] and Vanguard followed in 1960.[74] All other surviving British battleships had been sold or broken up by 1949.[75] The Soviet Union's Marat was scrapped in 1953, Parizhskaya Kommuna in 1957 and Oktyabrskaya Revolutsiya (back under her original name, Gangut, since 1942)[76] in 1956-7.[76] Brazil's Minas Geraes was scrapped in Genoa in 1953,[77] and her sister ship São Paulo sank during a storm in the Atlantic en route to the breakers in Italy in 1951.[77]
Argentina kept its two Rivadavia-class ships until 1956 and Chile kept Almirante Latorre (formerly HMSCanada) until 1959.[78] The Turkish battlecruiser Yavûz (formerly SMSGoeben, launched in 1911) was scrapped in 1976 after an offer to sell her back to Germany was refused. Sweden had several small coastal-defense battleships, one of which, HSwMSGustav V, survived until 1970.[79] The Soviets scrapped four large incomplete cruisers in the late 1950s, whilst plans to build a number of new Stalingrad-class battlecruisers were abandoned following the death of Joseph Stalin in 1953.[80] The three old German battleships Schleswig-Holstein, Schlesien, and Hessen all met similar ends. Hessen was taken over by the Soviet Union and renamed Tsel. She was scrapped in 1960. Schleswig-Holstein was renamed Borodino, and was used as a target ship until 1960. Schlesien, too, was used as a target ship. She was broken up between 1952 and 1957.[81]

The Iowa-class battleships gained a new lease of life in the U.S. Navy as fire support ships. Radar and computer-controlled gunfire could be aimed with pinpoint accuracy to target. The U.S. recommissioned all four Iowa-class battleships for the Korean War and the New Jersey for the Vietnam War. These were primarily used for shore bombardment, New Jersey firing nearly 6,000 rounds of 16inch shells and over 14,000 rounds of 5inch projectiles during her tour on the gunline,[82] seven times more rounds against shore targets in Vietnam than she had fired in the Second World War.[83]
As part of Navy Secretary John F. Lehman's effort to build a 600-ship Navy in the 1980s, and in response to the commissioning of Kirov by the Soviet Union, the United States recommissioned all four Iowa-class battleships. On several occasions, battleships were support ships in carrier battle groups, or led their own battleship battle group. These were modernized to carry Tomahawk (TLAM) missiles, with New Jersey seeing action bombarding Lebanon in 1983 and 1984, while Missouri and Wisconsin fired their 16-inch (406mm) guns at land targets and launched missiles during Operation Desert Storm in 1991. Wisconsin served as the TLAM strike commander for the Persian Gulf, directing the sequence of launches that marked the opening of Desert Storm, firing a total of 24 TLAMs during the first two days of the campaign. The primary threat to the battleships were Iraqi shore-based surface-to-surface missiles; Missouri was targeted by two Iraqi Silkworm missiles, with one missing and another being intercepted by the British destroyer HMSGloucester.[84]
End of the battleship era

After Indiana was stricken in 1962, the four Iowa-class ships were the only battleships in commission or reserve anywhere in the world. There was an extended debate when the four Iowa ships were finally decommissioned in the early 1990s. USSIowa and USSWisconsin were maintained to a standard where they could be rapidly returned to service as fire support vessels, pending the development of a superior fire support vessel. These last two battleships were finally stricken from the U.S. Naval Vessel Register in 2006.[85][86][87]  The Military Balance and Russian Foreign Military Review states the U.S. Navy listed one battleship in the reserve (Naval Inactive Fleet/Reserve 2nd Turn) in 2010.[88][89] The Military Balance states the U.S. Navy listed no battleships in the reserve in 2014.[90] The U.S. Marine Corps believes that the current naval surface fire support gun and missile programs will not be able to provide adequate fire support for an amphibious assault or onshore operations.[91][92]
When the last Iowa-class ship was finally stricken from the Naval Vessel Registry, no battleships remained in service or in reserve with any navy worldwide. A number are preserved as museum ships, either afloat or in drydock. The U.S. has eight battleships on display: Massachusetts, North Carolina, Alabama, Iowa, New Jersey, Missouri, Wisconsin, and Texas.  Missouri and New Jersey are museums at Pearl Harbor and Camden, New Jersey, respectively. Iowa is on display as an educational attraction at the Los Angeles Waterfront in San Pedro, California. Wisconsin now serves as a museum ship in Norfolk, Virginia.[93] Massachusetts, which has the distinction of never having lost a man during service, is on display at the Battleship Cove naval museum in Fall River, Massachusetts.[94] Texas, the first battleship turned into a museum, is on display at the San Jacinto Battleground State Historic Site, near Houston. North Carolina is on display in Wilmington, North Carolina. Alabama is on display in Mobile, Alabama. The wreck of the Arizona, sunk during the Pearl Harbor attack in 1941, is designated a historical landmark and national gravesite.
The only other 20th-century battleship on display is the Japanese pre-dreadnought Mikasa.  A replica of the Chinese ironclad Dingyuan was built by the Weihai Port Bureau in 2003 and is on display in Weihai, China.

Strategy and doctrine
Doctrine

Battleships were the embodiment of sea power. For Alfred Thayer Mahan and his followers, a strong navy was vital to the success of a nation, and control of the seas was vital for the projection of force on land and overseas.  Mahan's theory, proposed in The Influence of Sea Power Upon History, 1660–1783 of 1890, dictated the role of the battleship was to sweep the enemy from the seas.[95] While the work of escorting, blockading, and raiding might be done by cruisers or smaller vessels, the presence of the battleship was a potential threat to any convoy escorted by any vessels other than capital ships. This concept of "potential threat" can be further generalized to the mere existence (as opposed to presence) of a powerful fleet tying the opposing fleet down.  This concept came to be known as a "fleet in being" – an idle yet mighty fleet forcing others to spend time, resource and effort to actively guard against it.
Mahan went on to say victory could only be achieved by engagements between battleships, which came to be known as the decisive battle doctrine in some navies, while targeting merchant ships (commerce raiding or guerre de course, as posited by the Jeune École) could never succeed.[96]
Mahan was highly influential in naval and political circles throughout the age of the battleship,[2][97] calling for a large fleet of the most powerful battleships possible. Mahan's work developed in the late 1880s, and by the end of the 1890s it had acquired much international influence on naval strategy;[2] in the end, it was adopted by many major navies (notably the British, American, German, and Japanese).  The strength of Mahanian opinion was important in the development of the battleships arms races, and equally important in the agreement of the Powers to limit battleship numbers in the interwar era.
The "fleet in being" suggested battleships could simply by their existence tie down superior enemy resources.  This in turn was believed to be able to tip the balance of a conflict even without a battle. This suggested even for inferior naval powers a battleship fleet could have important strategic effect.[98]
Tactics
While the role of battleships in both World Wars reflected Mahanian doctrine, the details of battleship deployment were more complex. Unlike ships of the line, the battleships of the late 19th and early 20th centuries had significant vulnerability to torpedoes and mines—because efficient mines and torpedoes did not exist before that[99]—which could be used by relatively small and inexpensive craft. The Jeune École doctrine of the 1870s and 1880s recommended placing torpedo boats alongside battleships; these would hide behind the larger ships until gun-smoke obscured visibility enough for them to dart out and fire their torpedoes.[2] While this tactic was vitiated by the development of smokeless propellant, the threat from more capable torpedo craft (later including submarines) remained. By the 1890s, the Royal Navy had developed the first destroyers, which were initially designed to intercept and drive off any attacking torpedo boats. During the First World War and subsequently, battleships were rarely deployed without a protective screen of destroyers.[100]
Battleship doctrine emphasised the concentration of the battlegroup. In order for this concentrated force to be able to bring its power to bear on a reluctant opponent (or to avoid an encounter with a stronger enemy fleet), battlefleets needed some means of locating enemy ships beyond horizon range. This was provided by scouting forces; at various stages battlecruisers, cruisers, destroyers, airships, submarines and aircraft were all used. (With the development of radio, direction finding and traffic analysis would come into play, as well, so even shore stations, broadly speaking, joined the battlegroup.[101]) So for most of their history, battleships operated surrounded by squadrons of destroyers and cruisers. The North Sea campaign of the First World War illustrates how, despite this support, the threat of mine and torpedo attack, and the failure to integrate or appreciate the capabilities of new techniques,[102] seriously inhibited the operations of the Royal Navy Grand Fleet, the greatest battleship fleet of its time.
Strategic and diplomatic impact
The presence of battleships had a great psychological and diplomatic impact. Similar to possessing nuclear weapons today, the ownership of battleships served to enhance a nation's force projection.[2]
Even during the Cold War, the psychological impact of a battleship was significant. In 1946, USS Missouri was dispatched to deliver the remains of the ambassador from Turkey, and her presence in Turkish and Greek waters staved off a possible Soviet thrust into the Balkan region.[103] In September 1983, when Druze militia in Lebanon's Shouf Mountains fired upon U.S. Marine peacekeepers, the arrival of USS New Jersey stopped the firing. Gunfire from New Jersey later killed militia leaders.[104]
Value for money
Battleships were the largest and most complex, and hence the most expensive warships of their time; as a result, the value of investment in battleships has always been contested. As the French politician Etienne Lamy wrote in 1879, "The construction of battleships is so costly, their effectiveness so uncertain and of such short duration, that the enterprise of creating an armored fleet seems to leave fruitless the perseverance of a people".[99] The Jeune École school of thought of the 1870s and 1880s sought alternatives to the crippling expense and debatable utility of a conventional battlefleet. It proposed what would nowadays be termed a sea denial strategy, based on fast, long-ranged cruisers for commerce raiding and torpedo boat flotillas to attack enemy ships attempting to blockade French ports. The ideas of the Jeune École were ahead of their time; it was not until the 20th century that efficient mines, torpedoes, submarines, and aircraft were available that allowed similar ideas to be effectively implemented.[99] The determination of powers such as Germany to build battlefleets with which to confront much stronger rivals has been criticised by historians, who emphasise the futility of investment in a battlefleet that has no chance of matching its opponent in an actual battle.[2]
See also

Arsenal ship
List of battleships
List of battleships by country
List of battleship classes
List of sunken battleships
List of ships of the Second World War
List of battleships of the Second World War
Notes

Corbett, Sir Julian. "Maritime Operations In The Russo-Japanese War 1904–1905." (1994). Originally Classified and in two volumes. ISBN1-55750-129-7.

Polmar, Norman. The Naval Institute Guide to the Ships and Aircraft of the US Fleet. 2001, Naval Institute Press. ISBN1-55750-656-6.

Further reading

Mahan, Alred Thayer. Reflections, Historic and Other, Suggested by the Battle of the Japan Sea. By Captain A. T. Mahan, US Navy. US Naval Proceedings magazine; June 1906, volume XXXIV, number 2. United States Naval Institute Press.

Taylor, Bruce, ed. The world of the battleship: The design and careers of capital ships of the world's navies, 1900-1950 (US Naval Institute Press, 2017) 224pp

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