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Choke (firearms)
A choke is a tapered constriction of a firearm gun barrel, barrel at its muzzle (firearm), muzzle end. Chokes are most commonly seen on shotguns, but are also used on some rifles, pistols, or even airguns. Notably, some .22 LR match rifles have a constricted bore diameter near the muzzle. Chokes are almost always used with modern hunting and target shotguns to improve performance. Their purpose is to shape the spread of the shot "cloud" or "string" to gain better range and accuracy, and to deliver the optimum pattern of pellet density, for the particular target, depending on its size, range, aspect and whether it is traveling towards, across or away from the shooter. Chokes are implemented as either screw-in chokes, selected for particular applications, or as fixed, permanent chokes, integral to the shotgun barrel. Chokes may be formed at the time of manufacture either as part of the barrel, by squeezing the end of the bore down over a mandrel, or by threading the barrel and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shooting Sports
Shooting sports is a group of competitive sport, competitive and recreational sporting activities involving proficiency tests of accuracy, precision and speed in shooting — the art of using ranged weapons, mainly small arms (firearms and airguns, in forms such as handguns, rifles and shotguns) and bow and arrow, bows/crossbows. Shooting sports can be categorized by equipment, shooting distances, shooting target, targets, time limits and degrees of sport of athletics, athleticism involved. Shooting sports may involve both team and individual competition, and team performance is usually assessed by summing the scores of the individual team members. Due to the noise of shooting and the high (and often lethal) impact (mechanics), impact energy of the projectiles, shooting sports are typically conducted at either designated permanent shooting ranges or temporary shooting fields in the area away from settlements. History Great Britain The National Rifle Association (United Kingdo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tungsten
Tungsten (also called wolfram) is a chemical element; it has symbol W and atomic number 74. It is a metal found naturally on Earth almost exclusively in compounds with other elements. It was identified as a distinct element in 1781 and first isolated as a metal in 1783. Its important ores include scheelite and wolframite, the latter lending the element its alternative name. The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all known elements, melting at . It also has the highest boiling point, at . Its density is 19.254 g/cm3, comparable with that of uranium and gold, and much higher (about 1.7 times) than that of lead. Polycrystalline tungsten is an intrinsically brittle and hard material (under standard conditions, when uncombined), making it difficult to work into metal. However, pure single-crystalline tungsten is more ductile and can be cut with a hard-steel hacksaw. Tungsten occurs in many alloys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead
Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable nuclide, stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its Amphoterism, amphoteric nature; lead and lead oxides react with acids and base (chemistry), bases, and it tends to form covalent bonds. Lead compounds, Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waterfowl
Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which includes over 170 species of waterfowl, among them the ducks, geese, and swans. Most modern species in the order are highly adapted for an aquatic existence at the water surface. With the exception of screamers, males have penises, a trait that has been lost in the Neoaves, the clade consisting of all other modern birds except the galliformes and paleognaths. Due to their aquatic nature, most species are web-footed. Evolution Anseriformes are one of only two types of modern bird to be confirmed present during the Mesozoic alongside the other dinosaurs, and in fact were among the very few birds to survive their extinction, along with their cousins, the Galliformes. These two groups only occupied two ecological niches during the Mesozoic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecotoxicology
Ecotoxicology is the study of the effects of toxic chemicals on biological organisms, especially at the population biology, population, biological community, community, ecosystem, and biosphere levels. Ecotoxicology is a multidisciplinary field, which integrates toxicology and ecology. The ultimate goal of ecotoxicology is to reveal and predict the effects of pollution within the context of all other environmental factors. Based on this knowledge the most efficient and effective action to prevent or remediate any detrimental effect can be identified. In those ecosystems that are already affected by pollution, ecotoxicological studies can inform the choice of action to restore ecosystem services, structures, and functions efficiently and effectively. Ecotoxicology differs from environmental toxicology in that it integrates the effects of stressors across all levels of biological organisation from the molecular to whole communities and ecosystems, whereas environmental toxicology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Poisoning
Lead poisoning, also known as plumbism and saturnism, is a type of metal poisoning caused by lead in the body. Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, infertility, numbness and paresthesia, tingling in the hands and feet. It causes almost 10% of intellectual disability of otherwise unknown cause and can result in behavioral problems. Some of the effects are permanent. In severe cases, anemia, seizures, coma, or death may occur. Exposure to lead can occur by contaminated air, water, dust, food, or consumer products. Lead poisoning poses a significantly increased risk to children and pets as they are far more likely to ingest lead indirectly by chewing on toys or other objects that are coated in lead paint. Additionally, children absorb greater quantities of lead from ingested sources than adults. Exposure at work is a common cause of lead poisoning in adults with certain occupations at particular risk. Diagnosis is typically b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
410 Bore
The .410 bore (10.4 mm) is a small caliber shotgun, firing one of the smallest commonly available shotgun shells. A .410 bore shotgun loaded with shot shells is well suited for small game hunting and pest control. The .410 started off in the United Kingdom as a garden gun along with the .360 and the No. 3 bore (9 mm) rimfire, No. 2 bore (7 mm) rimfire, and No. 1 bore (6 mm) rimfire. .410 shells have similar base dimensions to the .45 Colt cartridge, allowing many single-shot firearms, as well as derringers and revolvers chambered in that caliber, to fire .410 shot shells without any modifications. Other small bore shotgun loads include the 9mm Flobert rimfire cartridge, and the less prevalent .22 rimfire shot shell. Origin Lancaster's pattern centerfire and pinfire .410 shot cartridges first appeared in Eley Brothers Ltd. flysheets in 1857. By 1874, Eley was advertising modern centerfire .410 cartridges. It appears to have become popular around 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vietnam War
The Vietnam War (1 November 1955 – 30 April 1975) was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam (Democratic Republic of Vietnam) and South Vietnam (Republic of Vietnam) and their allies. North Vietnam was supported by the Soviet Union and China, while South Vietnam was supported by the United States and other anti-communist nations. The conflict was the second of the Indochina wars and a proxy war of the Cold War between the Soviet Union and US. The Vietnam War was one of the postcolonial wars of national liberation, a theater in the Cold War, and a civil war, with civil warfare a defining feature from the outset. Direct United States in the Vietnam War, US military involvement escalated from 1965 until its withdrawal in 1973. The fighting spilled into the Laotian Civil War, Laotian and Cambodian Civil Wars, which ended with all three countries becoming Communism, communist in 1975. After the defeat of the French Union in the First Indoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combat Shotgun
A combat shotgun is a shotgun issued by militaries for warfare. The earliest shotguns specifically designed for combat were the trench guns or trench shotguns issued in World War I. While limited in range, the multiple projectiles typically used in a shotgun shell increase the probability of hitting a target at close quarters. History While the sporting shotgun traces its ancestry back to the fowling piece, which was a refinement of the smoothbore musket, the combat shotgun bears more kinship to the shorter blunderbuss. Invented in the 16th century by the Dutch, the blunderbuss was used through the 18th century in warfare by the British, Austrian, Spanish (like the Escopeteros Voluntarios de Cadiz, formed in 1804, or the Compañía de Escopeteros de las Salinas, among others) and Prussian regiments, as well as in the American colonies. As use of the blunderbuss declined, the United States military began loading smaller lead shot (buckshot) in combination with their large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chokes Photos Tamil
Choking, also known as foreign body airway obstruction (FBAO), is a phenomenon that occurs when breathing is impeded by a blockage inside of the respiratory tract. An obstruction that prevents oxygen from entering the lungs results in oxygen deprivation. Although oxygen stored in the blood and lungs can keep a person alive for several minutes after breathing stops, choking often leads to death. Around 4,500 to 5,000 choking-related deaths occur in the United States every year. Deaths from choking most often occur in the very young (children under three years old) and in the elderly (adults over 75 years). Foods that can adapt their shape to that of the pharynx (such as bananas, marshmallows, or gelatinous candies) are more dangerous. Various forms of specific first aid are used to address and resolve choking. Choking is the fourth leading cause of unintentional injury death in the United States. Many episodes go unreported because they are brief and resolve without needing med ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gauge (bore Diameter)
The gauge (in American English or more commonly referred to as bore in British English) of a firearm is a unit of measurement used to express the inner diameter (bore diameter) and other necessary parameters to define in general a smoothbore Gun barrel, barrel (compare to caliber, which defines a barrel with rifling and its Cartridge (firearms), cartridge). The gauge of a shotgun is a list that includes all necessary data to define a functional barrel. For example, the dimension of the chamber, the shotgun bore dimension and the valid proof load and commercial ammunition, as defined globally by the Commission internationale permanente pour l'épreuve des armes à feu portatives, C.I.P.; defined in Great Britain by the ''Rules, regulations and scales applicable to the proof of small arms'' (2006) of Worshipful Company of Gunmakers, The London Proof House and Birmingham Proof House, The Birmingham Proof House, as referred in the Gun Barrel Proof Act 1978, Paragraph 6; and defined in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
