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Craig Harrison (sniper)
Craig Harrison (born November 1974) is a former Corporal of Horse (CoH) in the Blues and Royals, a cavalry regiment of the British Army, who from 2009 to 2017 held the record for the longest confirmed sniper kill in combat, at a range of . Craig Harrison is most famous for his military service in Afghanistan as a sniper but he also served in the British army in Iraq and the Balkans. Discovering sniping The first time Harrison used a sniper rifle was when firing a Dragunov sniper rifle (SVD) on a firing range near a British military base in Split, Croatia. In his autobiography ''The Longest Kill'', Harrison described the rifle as looking like "an elongated AK" and after firing at a tree he says it "practically split the tree in half". Record details In November 2009, Harrison consecutively struck two Taliban machine gunners south of Musa Qala in Helmand Province in Afghanistan at a range of using a L115A3 Long Range Rifle. In a BBC interview, Harrison reported it took about ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheltenham
Cheltenham (), also known as Cheltenham Spa, is a spa town and borough on the edge of the Cotswolds in the county of Gloucestershire, England. Cheltenham became known as a health and holiday spa town resort, following the discovery of mineral springs in 1716, and claims to be the most complete Regency town in Britain. The town hosts several festivals of culture, often featuring nationally and internationally famous contributors and attendees; they include the Cheltenham Literature Festival, the Cheltenham Jazz Festival, the Cheltenham Science Festival, the Cheltenham Music Festival, the Cheltenham Cricket Festival and the Cheltenham Food & Drink Festival. In steeplechase horse racing, the Gold Cup is the main event of the Cheltenham Festival, held every March. History Cheltenham stands on the small River Chelt, which rises nearby at Dowdeswell and runs through the town on its way to the Severn. It was first recorded in 803, as ''Celtan hom''; the meaning has not been resol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afghanistan
Afghanistan, officially the Islamic Emirate of Afghanistan,; prs, امارت اسلامی افغانستان is a landlocked country located at the crossroads of Central Asia and South Asia. Referred to as the Heart of Asia, it is bordered by Pakistan to the Durand Line, east and south, Iran to the Afghanistan–Iran border, west, Turkmenistan to the Afghanistan–Turkmenistan border, northwest, Uzbekistan to the Afghanistan–Uzbekistan border, north, Tajikistan to the Afghanistan–Tajikistan border, northeast, and China to the Afghanistan–China border, northeast and east. Occupying of land, the country is predominantly mountainous with plains Afghan Turkestan, in the north and Sistan Basin, the southwest, which are separated by the Hindu Kush mountain range. , Demographics of Afghanistan, its population is 40.2 million (officially estimated to be 32.9 million), composed mostly of ethnic Pashtuns, Tajiks, Hazaras, and Uzbeks. Kabul is the country's largest city and ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
External Ballistics
External ballistics or exterior ballistics is the part of ballistics that deals with the behavior of a projectile in flight. The projectile may be powered or un-powered, guided or unguided, spin or fin stabilized, flying through an atmosphere or in the vacuum of space, but most certainly flying under the influence of a gravitational field. Gun-launched projectiles may be unpowered, deriving all their velocity from the propellant's ignition until the projectile exits the gun barrel. However, exterior ballistics analysis also deals with the trajectories of rocket-assisted gun-launched projectiles and gun-launched rockets; and rockets that acquire all their trajectory velocity from the interior ballistics of their on-board propulsion system, either a rocket motor or air-breathing engine, both during their boost phase and after motor burnout. External ballistics is also concerned with the free-flight of other projectiles, such as balls, arrows etc. Forces acting on the projectile W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telescopic Sight
A telescopic sight, commonly called a scope informally, is an optical sighting device based on a refracting telescope. It is equipped with some form of a referencing pattern – known as a ''reticle'' – mounted in a focally appropriate position in its optical system to provide an accurate point of aim. Telescopic sights are used with all types of systems that require magnification in addition to reliable visual aiming, as opposed to non-magnifying iron sights, reflector (reflex) sights, holographic sights or laser sights, and are most commonly found on long-barrel firearms, particularly rifles, usually via a scope mount. The optical components may be combined with optoelectronics to add night vision or smart device features. History The first experiments directed to give shooters optical aiming aids go back to the early 17th century. For centuries, different optical aiming aids and primitive predecessors of telescopic sights were created that had practical or pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milliradian
A milliradian ( SI-symbol mrad, sometimes also abbreviated mil) is an SI derived unit for angular measurement which is defined as a thousandth of a radian (0.001 radian). Milliradians are used in adjustment of firearm sights by adjusting the angle of the sight compared to the barrel (up, down, left, or right). Milliradians are also used for comparing shot groupings, or to compare the difficulty of hitting different sized shooting targets at different distances. When using a scope with both mrad adjustment and a reticle with mrad markings (called an "mrad/mrad scope"), the shooter can use the reticle as a ruler to count the number of mrads a shot was off-target, which directly translates to the sight adjustment needed to hit the target with a follow up shot. Optics with mrad markings in the reticle can also be used to make a range estimation of a known size target, or vice versa, to determine a target size if the distance is known, a practice called "milling". Milliradian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Altitude
Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometry, geographical survey, sport, or atmospheric pressure). Although the term ''altitude'' is commonly used to mean the height above sea level of a location, in geography the term elevation is often preferred for this usage. Vertical distance measurements in the "down" direction are commonly referred to as depth. In aviation In aviation, the term altitude can have several meanings, and is always qualified by explicitly adding a modifier (e.g. "true altitude"), or implicitly through the context of the communication. Parties exchanging altitude information must be clear which definition is being used. Aviation altitude is measured using either mean sea level (MSL) or local ground level (above ground level, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density Of Air
The density of air or atmospheric density, denoted '' ρ'', is the mass per unit volume of Earth's atmosphere. Air density, like air pressure, decreases with increasing altitude. It also changes with variation in atmospheric pressure, temperature and humidity. At 101.325 kPa (abs) and 20 °C (68 °F), air has a density of approximately , according to the International Standard Atmosphere (ISA). At 101.325kPa (abs) and , air has a density of approximately , which is about that of water, according to the International Standard Atmosphere (ISA). Pure liquid water is . Air density is a property used in many branches of science, engineering, and industry, including aeronautics;Olson, Wayne M. (2000) AFFTC-TIH-99-01, Aircraft Performance FlightICAO, Manual of the ICAO Standard Atmosphere (extended to 80 kilometres (262 500 feet)), Doc 7488-CD, Third Edition, 1993, .Grigorie, T.L., Dinca, L., Corcau J-I. and Grigorie, O. (2010) Aircrafts' Altitude Measurement Using Pressure Information:Ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Standard Atmosphere
The International Standard Atmosphere (ISA) is a static atmospheric model of how the pressure, temperature, density, and viscosity of the Earth's atmosphere change over a wide range of altitudes or elevations. It has been established to provide a common reference for temperature and pressure and consists of tables of values at various altitudes, plus some formulas by which those values were derived. The International Organization for Standardization (ISO) publishes the ISA as an international standard, ISO 2533:1975.International Organization for Standardization, Standard Atmosphere', ISO 2533:1975, 1975. Other standards organizations, such as the International Civil Aviation Organization (ICAO) and the United States Government, publish extensions or subsets of the same atmospheric model under their own standards-making authority. Description The ISA mathematical model divides the atmosphere into layers with an assumed linear distribution of absolute temperature ''T'' against geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speed Of Sound
The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. At , the speed of sound in air is about , or one kilometre in or one mile in . It depends strongly on temperature as well as the medium through which a sound wave is propagating. At , the speed of sound in air is about . The speed of sound in an ideal gas depends only on its temperature and composition. The speed has a weak dependence on frequency and pressure in ordinary air, deviating slightly from ideal behavior. In colloquial speech, ''speed of sound'' refers to the speed of sound waves in air. However, the speed of sound varies from substance to substance: typically, sound travels most slowly in gases, faster in liquids, and fastest in solids. For example, while sound travels at in air, it travels at in water (almost 4.3 times as fast) and at in iron (almost 15 times as fast). In an exceptionally stiff material such as diamond, sound travels a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag Coefficient
In fluid dynamics, the drag coefficient (commonly denoted as: c_\mathrm, c_x or c_) is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment, such as air or water. It is used in the drag equation in which a lower drag coefficient indicates the object will have less aerodynamic or hydrodynamic drag. The drag coefficient is always associated with a particular surface area. The drag coefficient of any object comprises the effects of the two basic contributors to fluid dynamic drag: skin friction and form drag. The drag coefficient of a lifting airfoil or hydrofoil also includes the effects of lift-induced drag. The drag coefficient of a complete structure such as an aircraft also includes the effects of interference drag. Definition The drag coefficient c_\mathrm d is defined as c_\mathrm d = \dfrac where: * F_\mathrm d is the drag force, which is by definition the force component in the direction of the flow velocity; * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stadiametric Rangefinding
Stadiametric rangefinding, or the stadia method, is a technique of measuring distances with a telescopic instrument. The term stadia comes from a Greek unit of length '' Stadion'' (equal to 600 Greek feet, ''pous'') which was the typical length of a sports stadium of the time. Stadiametric rangefinding is used for surveying and in the telescopic sights of firearms, artillery pieces, or tank guns, as well as some binoculars and other optics. It is still widely used in long-range military sniping, but in many professional applications it is being replaced with microwave, infrared, or laser rangefinding methods. Although much easier to use, electronic rangefinders can give away the shooter's position to a well-equipped adversary, and the need for accurate range estimation existed for much longer than electronic rangefinders small and rugged enough to be suitable for military use. Principle The stadia method is based upon the principle of similar triangles. This means that, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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