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Smooth-bore
A smoothbore weapon is one that has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars. History Early firearms had smoothly bored barrels that fired projectiles without significant spin. To minimize inaccuracy-inducing tumbling during flight, their projectiles required an aerodynamically uniform shape, such as a sphere. However, surface imperfections on the projectile and/or the barrel will cause even a sphere to rotate randomly during flight, and the Magnus effect will curve it off the intended trajectory when spinning on any axis not parallel to the direction of travel. Rifling the bore surface with spiral grooves or polygonal valleys imparts a stabilizing gyroscopic spin to a projectile that prevents tumbling in flight. Not only does this more than counter Magnus-induced drift, but it allows a longer, more streamlined round with greater sectional density to be fired from the same caliber barrel, improvin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mortar (weapon)
A mortar is usually a simple, lightweight, man-portable, muzzle-loaded weapon, consisting of a smooth-bore (although some models use a rifled barrel) metal tube fixed to a base plate (to spread out the recoil) with a lightweight bipod mount and a sight. They launch explosive shells (technically called bombs) in high-arcing ballistic trajectories. Mortars are typically used as indirect fire weapons for close fire support with a variety of ammunition. History Mortars have been used for hundreds of years. The earliest mortars were used in Korea in a 1413 naval battle when Korean gunsmiths developed the ''wan'gu'' (gourd-shaped mortar) (완구, 碗口). The earliest version of the ''wan'gu'' dates back to 1407. Choi Hae-san (최해산, 崔海山) (1380–1443), the son of Choe Mu-seon (최무선, 崔茂宣) (1325–1395), is generally credited with inventing the ''wan'gu''. In the Ming dynasty, general Qi Jiguang recorded the use of a mini cannon called the Hu dun pao that was simi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Firearms
A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions). The first firearms originated in 10th-century China, when bamboo tubes containing gunpowder and pellet projectiles were mounted on spears to make the portable fire lance, operable by a single person, which was later used effectively as a shock weapon in the Siege of De'an in 1132. In the 13th century, fire lance barrels were replaced with metal tubes and transformed into the metal-barreled hand cannon. The technology gradually spread throughout Eurasia during the 14th century. 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. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artillery
Artillery is a class of heavy military ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during sieges, and led to heavy, fairly immobile siege engines. As technology improved, lighter, more mobile field artillery cannons developed for battlefield use. This development continues today; modern self-propelled artillery vehicles are highly mobile weapons of great versatility generally providing the largest share of an army's total firepower. Originally, the word "artillery" referred to any group of soldiers primarily armed with some form of manufactured weapon or armor. Since the introduction of gunpowder and cannon, "artillery" has largely meant cannons, and in contemporary usage, usually refers to shell-firing guns, howitzers, and mortars (collectively called ''barrel artillery'', ''cannon artillery'', ''gun artillery'', or - a layman t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gun Barrel
A gun barrel is a crucial part of gun-type weapons such as small firearms, artillery pieces, and air guns. It is the straight shooting tube, usually made of rigid high-strength metal, through which a contained rapid expansion of high-pressure gas(es) is used to propel a projectile out of the front end ( muzzle) at a high velocity. The hollow interior of the barrel is called the bore, and the diameter of the bore is called its caliber, usually measured in inches or millimetres. The first firearms were made at a time when metallurgy was not advanced enough to cast tubes capable of withstanding the explosive forces of early cannons, so the pipe (often built from staves of metal) needed to be braced periodically along its length for structural reinforcement, producing an appearance somewhat reminiscent of storage barrels being stacked together, hence the English name.''A History of Warfare'' - Keegan, John, Vintage 1993. History Gun barrels are usually metal. However, the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minié Ball
The Minié ball or Minie ball, is a type of hollow-based bullet designed by Claude-Étienne Minié, inventor of the French Minié rifle, for muzzle-loading rifled muskets. It was invented in 1847 and came to prominence in the Crimean War and the American Civil War, where it was found to inflict significantly more serious wounds than earlier round musket balls. Both the American Springfield Model 1861 and the British Pattern 1853 Enfield rifled muskets, the most common weapons used during the American Civil War, used the Minié ball. Rifling, the addition of spiral grooves inside a gun barrel, imparts a stabilizing spin to a projectile for better external ballistics, greatly increasing the effective range and accuracy of the gun. Before the introduction of the Minié ball, balls had to be rammed down the barrel, sometimes with a mallet, because gunpowder residue would foul a rifled bore after a relatively small number of shots, requiring frequent cleaning of the gun. McPher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density
Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematically, density is defined as mass divided by volume: : \rho = \frac where ''ρ'' is the density, ''m'' is the mass, and ''V'' is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume, although this is scientifically inaccurate – this quantity is more specifically called specific weight. For a pure substance the density has the same numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging. Osmium and iridium are the densest known elements at standard conditions for temperature and pressure. To simplify comparisons of density across different s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrifugal Force
In Newtonian mechanics, the centrifugal force is an inertial force (also called a "fictitious" or "pseudo" force) that appears to act on all objects when viewed in a rotating frame of reference. It is directed away from an axis which is parallel to the axis of rotation and passing through the coordinate system's origin. If the axis of rotation passes through the coordinate system's origin, the centrifugal force is directed radially outwards from that axis. The magnitude of centrifugal force ''F'' on an object of mass ''m'' at the distance ''r'' from the origin of a frame of reference rotating with angular velocity is: F = m\omega^2 r The concept of centrifugal force can be applied in rotating devices, such as centrifuges, centrifugal pumps, centrifugal governors, and centrifugal clutches, and in centrifugal railways, planetary orbits and banked curves, when they are analyzed in a rotating coordinate system. Confusingly, the term has sometimes also been used for the reactiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Shot
Shot is a collective term for small spheres or pellets, often made of lead. These were the original projectiles for shotguns and are still fired primarily from shotguns and less commonly from riot guns and grenade launchers, although shot shells are available in many pistol calibers in a configuration called "birdshot", "rat-shot", or "snake shot". Lead shot is also used for a variety of other purposes such as filling cavities with dense material for weight/balance. Some versions may be plated with other metals. Lead shot was originally made by pouring molten lead through screens into water, forming what was known as "swan shot", and, later, more economically mass-produced at higher quality using a shot tower. The ''Bliemeister method'' has supplanted the shot tower method since the early 1960s. Manufacture Producing lead shot from a shot tower was pioneered in the late 18th century by William Watts of Bristol who adapted his house on Redcliffe Hill by adding a three-storey t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shotgun
A shotgun (also known as a scattergun, or historically as a fowling piece) is a long gun, long-barreled firearm designed to shoot a straight-walled cartridge (firearms), cartridge known as a shotshell, which usually discharges numerous small pellets (petrology), pellet-like spherical sub-projectiles called shot (pellet), shot, or sometimes a single solid projectile called a shotgun slug, slug. Shotguns are most commonly smoothbore firearms, meaning that their gun barrels have no rifling on the inner wall, but rifled barrels for shooting slugs (slug barrels) are also available. Shotguns come in a wide variety of calibers and Gauge (firearms), gauges ranging from 5.5 mm (.22 inch) to up to , though the 12-gauge (18.53 mm or 0.729 in) and 20-gauge (15.63 mm or 0.615 in) bores are by far the most common. Almost all are breechloading, and can be single-barreled, double barreled shotgun, double-barreled, or in the form of a combination gun. Like rifles, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grand Turk(28)
Grand Turk Island is an island in the Turks and Caicos Islands. It is the largest island in the Turks Islands (the smaller of the two archipelagos that make up the island territory) with . Grand Turk contains the territory's capital, Cockburn Town, and the JAGS McCartney International Airport. The island is the administrative, historic, cultural and financial center of the territory and has the second-largest population of the islands at approximately 4,831 people in 2012. The name comes from a species of cactus on the island, the Turk's Cap Cactus (''Melocactus intortus''), which has a distinctive cap, reminiscent of an Ottoman fez. History The Lucayan people were the indigenous people of the island, who called it ''Abawana,'' meaning "the First Small Land"''.'' The Spanish later called it Amuana. Grand Turk was first colonised in 1681 by Bermudians, who set up the salt industry in the islands. In 1766 it became the capital of the country. For some time, at least until the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twin Sisters, San Jacinto
Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of TwinLast Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or ''dizygotic'' ('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell. Since identical twins develop from one zygote, they will share the same sex, while fraternal twins may or may not. In rare cases twins can have the same mother and different fathers (heteropaternal superfecundation). In contrast, a fetus that develops alone in the womb (the much more common case, in humans) is called a ''singleton'', and the general term for one offspring of a multiple birth is a ''multiple''. Unrelated look-alikes whose resemblance parallels that of twins are referred to as doppelgängers. Statistics The human twin birth rate in the United States rose 76% from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parrott Rifle
The Parrott rifle was a type of muzzle-loading rifled artillery weapon used extensively in the American Civil War. Parrott rifle The gun was invented by Captain Robert Parker Parrott, a West Point graduate. He was an American soldier and inventor of military ordnance. He resigned from the service in 1836 and became the superintendent of the West Point Foundry in Cold Spring, New York. He created the first Parrott rifle (and corresponding projectile) in 1860 and patented it in 1861.Pritchard Jr, Russ A.Civil War Weapons and Equipment, p.82. Globe Pequit Press, 2003. . Daniel Treadwell, who developed a method for making built-up guns in early 1840s, tried to claim that his patent infringed on an earlier one, but in 1866 S.D.N.Y. court dismissed it, deciding that Treadwell's claim was invalidated by a 1843 British patent to John Frith. Parrotts were manufactured with a combination of cast and wrought iron. The cast iron made for an accurate gun, but was brittle enough to suffer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
