1.
World War II
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World War II, also known as the Second World War, was a global war that lasted from 1939 to 1945, although related conflicts began earlier. It involved the vast majority of the worlds countries—including all of the great powers—eventually forming two opposing alliances, the Allies and the Axis. It was the most widespread war in history, and directly involved more than 100 million people from over 30 countries. Marked by mass deaths of civilians, including the Holocaust and the bombing of industrial and population centres. These made World War II the deadliest conflict in human history, from late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, and formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Poland, Finland, Romania and the Baltic states. In December 1941, Japan attacked the United States and European colonies in the Pacific Ocean, and quickly conquered much of the Western Pacific. The Axis advance halted in 1942 when Japan lost the critical Battle of Midway, near Hawaii, in 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained all of its territorial losses and invaded Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in South Central China and Burma, while the Allies crippled the Japanese Navy, thus ended the war in Asia, cementing the total victory of the Allies. World War II altered the political alignment and social structure of the world, the United Nations was established to foster international co-operation and prevent future conflicts. The victorious great powers—the United States, the Soviet Union, China, the United Kingdom, the Soviet Union and the United States emerged as rival superpowers, setting the stage for the Cold War, which lasted for the next 46 years. Meanwhile, the influence of European great powers waned, while the decolonisation of Asia, most countries whose industries had been damaged moved towards economic recovery. Political integration, especially in Europe, emerged as an effort to end pre-war enmities, the start of the war in Europe is generally held to be 1 September 1939, beginning with the German invasion of Poland, Britain and France declared war on Germany two days later. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or even the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred simultaneously and this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935. The British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the forces of Mongolia and the Soviet Union from May to September 1939, the exact date of the wars end is also not universally agreed upon. It was generally accepted at the time that the war ended with the armistice of 14 August 1945, rather than the formal surrender of Japan
2.
Watervliet Arsenal
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The Watervliet Arsenal /ˈwɔːtərvliːt/ is an arsenal of the United States Army located in Watervliet, New York, on the west bank of the Hudson River. It is the oldest continuously active arsenal in the United States, and today much of the artillery for the army, as well as gun tubes for cannons, mortars. It has been a National Historic Landmark since 1966, the arsenal was founded in 1813 to support the War of 1812, and was designated as the Watervliet Arsenal in 1817. It occupies 142 acres of land, approximately 8 miles north of Albany, the location is adjacent to the Hudson River. The site contains manufacturing, administrative offices and storage areas and it also houses the Armys Benet Laboratories, which does product development, improvement, research, and testing. The Arsenal has the historic Iron Building, which served as the home of the Watervliet Arsenal Museum, however, the museum was closed on October 1,2013 for security reasons. Recruiting Station Albany, the headquarters of a United States Marine Corps recruiting station, is located on the Arsenal, during the early stages of the War of 1812, attacks could be expected from many key ports and other locations. The original plot of land acquired by the Department of Ordnance was 12 acres, the cost for the land was US$2,585. During this period, production moved from the manufacturing of saddles, remnants of this period are still in operation today as evidenced by the continued use of historic Building 110, “The Big Gun Shop, ” for manufacturing missions. This gun shop once produced 16-inch guns and many weapons for the United States Army Coast Artillery Corps
3.
Shell (projectile)
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A shell is a payload-carrying projectile that, as opposed to shot, contains an explosive or other filling, though modern usage sometimes includes large solid projectiles properly termed shot. Solid shot may contain a pyrotechnic compound if a tracer or spotting charge is used, originally, it was called a bombshell, but shell has come to be unambiguous in a military context. Words cognate with grenade are still used for an artillery or mortar projectile in some European languages, shells are usually large-calibre projectiles fired by artillery, combat vehicles, and warships. Shells usually have the shape of a cylinder topped by a nose for good aerodynamic performance, possibly with a tapering base. Solid cannonballs did not need a fuse, but hollow munitions filled with something such as gunpowder to fragment the ball, needed a fuse, percussion fuses with a spherical projectile presented a challenge because there was no way of ensuring that the impact mechanism hit the target. Therefore, shells needed a fuse that was ignited before or during firing. The earliest record of shells being used in combat was by the Republic of Venice at Jadra in 1376, shells with fuses were used at the 1421 siege of St Boniface in Corsica. These were two hollowed hemispheres of stone or bronze held together by an iron hoop, as described in their book, these hollow, gunpowder-packed shells were made of cast iron. At least since the 16th Century grenades made of ceramics or glass were in use in Central Europe, a hoard of several hundred ceramic greandes were discovered during building works in front of a bastion of the Bavarian City of Ingolstadt, Germany dated to the 17th Century. Lots of the grenades obtained their orignal blackpowder loads and igniters, most probably the grenades were intentionally dumped the moat of the bastion before the year 1723. Early powder burning fuses had to be loaded fuse down to be ignited by firing or a portfire put down the barrel to light the fuse, other shells were wrapped in bitumen cloth, which would ignite during the firing and in turn ignite a powder fuse. Nevertheless, shells came into use in the 16th Century. By the 18th Century, it was known that the fuse towards the muzzle could be lit by the flash through the windage between the shell and the barrel, the use of exploding shells from field artillery became relatively commonplace from early in the 19th century. Until the mid 19th century, shells remained as simple exploding spheres that used gunpowder and they were usually made of cast iron, but bronze, lead, brass and even glass shell casings were experimented with. The word bomb encompassed them at the time, as heard in the lyrics of The Star-Spangled Banner, typically, the thickness of the metal body was about a sixth of their diameter and they were about two thirds the weight of solid shot of the same calibre. To ensure that shells were loaded with their fuses towards the muzzle, in 1819, a committee of British artillery officers recognised that they were essential stores and in 1830 Britain standardised sabot thickness as a half inch. The sabot was also intended to reduce jamming during loading, despite the use of exploding shell, the use of smoothbore cannons, firing spherical projectiles of shot, remained the dominant artillery method until the 1850s. By the late 18th century, artillery could use canister shot to defend itself from infantry or cavalry attack and this involved loading a tin or canvas container filled with small iron or lead balls instead of the usual cannonball
4.
Caliber
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In guns, particularly firearms, caliber or calibre is the approximate internal diameter of the barrel, or the diameter of the projectile it fires, in hundredths or sometimes thousandths of an inch. For example, a 45 caliber firearm has a diameter of.45 of an inch. Barrel diameters can also be expressed using metric dimensions, as in 9mm pistol, when the barrel diameter is given in inches, the abbreviation cal can be used. Good performance requires a bullet to closely match the diameter of a barrel to ensure a good seal. While modern cartridges and cartridge firearms are referred to by the cartridge name. Firearm calibers outside the range of 17 to 50 exist, but are rarely encountered. Larger calibers, such as.577.585.600.700, the.950 JDJ is the only known cartridge beyond 79 caliber used in a rifle. Referring to artillery, caliber is used to describe the length as multiples of the bore diameter. A 5-inch 50 calibre gun has a diameter of 5 in. The main guns of the USS Missouri are 1650 caliber, makers of early cartridge arms had to invent methods of naming the cartridges, since no established convention existed then. One of the early established cartridge arms was the Spencer repeating rifle, later various derivatives were created using the same basic cartridge, but with smaller-diameter bullets, these were named by the cartridge diameter at the base and mouth. The original No.56 became the. 56-56, and the smaller versions. 56-52. 56-50, the. 56-52, the most common of the new calibers, used a 50-cal bullet. Optionally, the weight in grains was designated, e. g. 45-70-405. Variations on these methods persist today, with new cartridges such as the.204 Ruger, metric diameters for small arms refer to cartridge dimensions and are expressed with an × between the bore diameter and the length of the cartridge case, for example,7. 62×51 NATO. This indicates that the diameter is 7. 62mm, loaded in a case 51mm long. Similarly, the 6. 5×55 Swedish cartridge has a diameter of 6.5 mm. An exception to rule is the proprietary cartridge used by U. S. maker Lazzeroni. The following table lists commonly used calibers where both metric and imperial are used as equivalents
5.
Breech-loading weapon
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A breech-loading gun is a firearm in which the cartridge or shell is inserted or loaded into a chamber integral to the rear portion of a barrel. Modern mass production firearms are breech-loading, early firearms, on the other hand, were almost entirely muzzle-loading. In field artillery, breech loading allows the crew to reload the gun without exposing themselves to fire or repositioning the piece. The main challenge for developers of breech-loading firearms was sealing the breech and this was eventually solved for smaller firearms by the development of the self-contained metallic cartridge. For firearms too large to use cartridges, the problem was solved by the development of the interrupted screw, breech-loading swivel guns were invented in the 14th century. The breech-loading swivel gun had a rate of fire, and was especially effective in anti-personnel roles. Breech-loading firearms are known from the 16th century, Henry VIII possessed one, which he apparently used as a hunting gun to shoot birds. More breech-loading firearms were made in the early 18th century, one such gun known to have belonged to Philip V of Spain, and was manufactured circa 1715, probably in Madrid. It came with a ready-to load reusable cartridge, patrick Ferguson, a British Army officer, developed in 1772 the Ferguson rifle, a breech-loading flintlock firearm. Later on into the century there were attempts in Europe at an effective breech-loader. There were concentrated attempts at improved cartridges and methods of ignition, the cartridge was loaded through the breech and fired with a needle. The needle-activated central-fire breech-loading gun would become a feature of firearms thereafter. The corresponding firearm was also developed by Pauly, Pauly made an improved version, which was protected by a patent on 29 September 1812. In 1846 another Paris Frenchman, Benjamin Houllier, patented the first fully metallic cartridge containing powder in a metallic shell, Houllier commercialised his weapons in association with the gunsmiths Blanchard or Charles Robert. In English-speaking countries the Flobert cartridge corresponds to the.22 BB, the first centrefire cartridge was introduced in 1855 by Pottet, with both Berdan and Boxer priming. The Dreyse Zündnadelgewehr or Dreyse needle gun, was a single-shot breech-loading rifle using a rotating bolt to seal the breech and it was so called because of its. 5-inch needle-like firing pin, which passed through a paper cartridge case to impact a percussion cap at the bullet base. It began development in the 1830s under von Dreyse and eventually a version of it was adopted by Prussia in the late 1840s. The paper cartridge and the gun had numerous deficiencies, specifically, however, the rifle was used to great success in the Prussian army in the Austro-Prussian war of 1866
6.
Interrupted screw
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An interrupted screw or interrupted thread is a mechanical device typically used in the breech of artillery guns. It is believed to have invented in 1845. It is a screw that has a section of thread along its axis removed, the screw is mated with a partially threaded hole at the rear of the weapons chamber, where the screw has threads the hole has none, and vice versa. The screw can thus be smoothly inserted all the way into the gun, an earlier method was the use of a wedge to block the rear of the gun. Sealing was further improved with the de Bange obturator in 1872, the major weakness of the original designs was that only half of the circumference of the breechblock could be threaded, hence a fairly long breechblock was still required to achieve a secure lock. Axel Welin solved this problem with his stepped interrupted screw design and this design has threads of the block and breech cut in steps of successively larger radius. This is the design still in use with bagged charge artillery. Rifled breech loader Welin breech block Interrupted screw breech mechanisms Navweaps. com Interrupted threads used on naval guns
7.
Recoil
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Recoil is the backward movement of a gun when it is discharged. To apply this counter-recoiling force, modern mounted guns may employ recoil buffering comprising springs and hydraulic recoil mechanisms, early cannons used systems of ropes along with rolling or sliding friction to provide forces to slow the recoiling cannon to a stop. Recoil buffering allows the maximum counter-recoil force to be lowered so that strength limitations of the gun mount are not exceeded, however, the same pressures acting on the base of the projectile are acting on the rear face of the gun chamber, accelerating the gun rearward during firing. This results in the required counter-recoiling force being proportionally lower, modern cannons also employ muzzle brakes very effectively to redirect some of the propellant gasses rearward after projectile exit. This provides a force to the barrel, allowing the buffering system. The same physics affecting recoil in mounted guns and cannons applies to hand-held guns, hands, arms and shoulders have considerable strength and elasticity for this purpose, up to certain practical limits. For this reason, establishing recoil safety standards for small arms remains challenging, a change in momentum of a mass requires a force, according to Newtons first law, known as the law of inertia, inertia simply being another term for mass. That force, applied to a mass, creates an acceleration, according to Newtons second law, the law of momentum -- changing the velocity of the mass changes its momentum. It is important to understand at this point that velocity is not simply speed, velocity is the speed of a mass in a particular direction. In a very technical sense, speed is a scalar, a magnitude, in summation, the total momentum of the system equals zero, surprisingly just as it did before the trigger was pulled. There are two conservation laws at work when a gun is fired, conservation of momentum and conservation of energy, recoil is explained by the law of conservation of momentum, and so it is easier to discuss it separately from energy. The nature of the process is determined by the force of the expanding gases in the barrel upon the gun. It is also determined by the force applied to the gun. The recoil force only acts during the time that the ejecta are still in the barrel of the gun, except for the case of zero-recoil, the counter-recoil force is smaller than the recoil force but lasts for a longer time. Since the recoil force and the force are not matched. In the zero-recoil case, the two forces are matched and the gun will not move when fired. In most cases, a gun is very close to a free-recoil condition, an example of near zero-recoil would be a gun securely clamped to a massive or well-anchored table, or supported from behind by a massive wall. For example, placing the butt of a large caliber gun directly against a wall, the recoil of a firearm, whether large or small, is a result of the law of conservation of momentum
8.
Gun laying
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Gun laying is the process of aiming an artillery piece, such as a gun, howitzer or mortar on land, or at sea, against surface or air targets. It may be laying for direct fire, where the gun is aimed similarly to a rifle, or indirect fire, the term includes automated aiming using, for example, radar-derived target data and computer-controlled guns. Gun laying means moving the axis of the bore of the barrel in two planes, horizontal and vertical. A gun is traversed – rotated in a horizontal plane – to align it with the target, Gun laying is a set of actions to align the axis of a gun barrel so that it points in the required direction. This alignment is in the horizontal and vertical planes, Gun laying may be for direct fire, where the layer sees the target, or indirect fire, where the target may not be visible from the gun. Gun laying has sometimes called training the gun. Laying in the vertical plane uses data derived from trials or empirical experience, for any given gun and projectile types, it reflects the distance to the target and the size of the propellant charge. It also incorporates any differences in height between gun and target, with indirect fire, it may allow for other variables as well. With indirect fire the horizontal angle is relative to something, typically the guns aiming point, depending on the gun mount, there is usually a choice of two trajectories. The dividing angle between the trajectories is about 45 degrees, it varies due to gun dependent factors. Below 45 degrees the trajectory is called low angle, above is high angle, the differences are that low angle fire has a shorter time of flight, a lower vertex and flatter angle of descent. All guns have carriages or mountings that support the barrel assembly, early guns could only be traversed by moving their entire carriage or mounting, and this lasted with heavy artillery into World War II. Mountings could be fitted into traversing turrets on ships, coast defences or tanks, from circa 1900 field artillery carriages provided traverse without moving the wheels and trail. The carriage, or mounting, also enabled the barrel to be set at the elevation angle. With some gun mounts it is possible to depress the gun, some guns require a near-horizontal elevation for loading. An essential capability for any elevation mechanism is to prevent the weight of the barrel forcing its heavier end downward and this is greatly helped by having trunnions at the centre of gravity, although a counterbalance mechanism can be used. It also means the elevation gear has to be enough to resist considerable downward pressure. However, mortars, where the forces were transferred directly into the ground
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