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Dry Fire
Dry firing is the practice of simulating the discharge of a firearm without any live ammunition, or practicing with an inert laser/infrared training platform and may also include the use of a target/feedback system. The terms also commonly refers to simply "firing" a gun that has no ammunition in it. Concern is commonly expressed that doing so might damage the gun. Dry fire does not pose any real risk of damage to most modern centerfire firearms; however, it can for rimfire weapons, where the firing pin in most designs will impact the breech face if the weapon is dry-fired. Because of this, precautions (such as the use of snap caps) are recommended if such a weapon is to be deliberately dry-fired. Purpose Dry firing is the practice of simulating the discharge of a firearm without any live ammunition, or practicing with an inert laser/infrared training platform such as an iMarksman or SIRT training pistol, and may also include the use of a target/feedback system, suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gun Safes For Visitors Firearms At A Courthouse In Prague, Czech Republic
A gun is a ranged weapon designed to use a shooting tube (gun barrel) to launch projectiles. The projectiles are typically solid, but can also be pressurized liquid (e.g. in water guns/water cannon, cannons, spray nozzle, spray guns for spray painting, painting or pressure washing, projected water disruptors, and technically also flamethrowers), gas (e.g. light-gas gun) or even charged particles (e.g. plasma torch, plasma gun). Solid projectiles may be free-flying (as with bullets and artillery shells) or tethered (as with Taser guns, spearguns and harpoon guns). A large-caliber gun is also called a ''cannon''. The means of projectile propulsion vary according to designs, but are traditionally effected pneumatically by a high gas pressure contained within the barrel tube, produced either through the rapid exothermic combustion of propellants (as with firearms), or by mechanical compression (as with air guns). The high-pressure gas is introduced behind the projectile, pushing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anchor
An anchor is a device, normally made of metal , used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ''ancora'', which itself comes from the Greek ἄγκυρα (ankȳra). Anchors can either be temporary or permanent. Permanent anchors are used in the creation of a mooring, and are rarely moved; a specialist service is normally needed to move or maintain them. Vessels carry one or more temporary anchors, which may be of different designs and weights. A sea anchor is a drag device, not in contact with the seabed, used to minimise drift of a vessel relative to the water. A drogue is a drag device used to slow or help steer a vessel running before a storm in a following or overtaking sea, or when crossing a bar in a breaking sea.. Overview Anchors achieve holding power either by "hooking" into the seabed, or mass, or a combination of the two. Permanent moorings use large masses (com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hang Fire
Hang fire refers to an unexpected delay between the triggering of a firearm and the ignition of the propellant. This failure was common in firearm actions that relied on open primer pans, due to the poor or inconsistent quality of the powder. Modern firearms are also susceptible. The delay is usually too brief to be noticed, but can be several seconds. A hangfire should be suspected whenever a firearm fails to fire, but has not clearly malfunctioned. Ignition sequence The ignition train of modern firearms begins with detonation of a small quantity of impact-sensitive primary explosive in a primer in cartridge firearms or in a percussion cap in muzzleloaders. The energy released by this detonation is intended to ignite the propellant charge of gunpowder or smokeless powder. Primary explosives may deteriorate with age so they release less energy; and propellants damaged by moisture or lubricants may require more energy to ignite. These conditions may either delay the ignition seq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gun Safety
Gun safety is the study and practice of using, transporting, storing and disposing of firearms and ammunition, including the training of gun users, the design of weapons, and formal and informal regulation of gun production, distribution, and usage, for the purpose of avoiding unintentional injury, illness, or death. This includes mishaps like accidental discharge, negligent discharge, and firearm malfunctions, as well as secondary risks like hearing loss, lead poisoning from bullets, and pollution from other hazardous materials in propellants and cartridges. There were 47,000 unintentional firearm deaths worldwide in 2013. History Accidental explosions of stored gunpowder date to the 13th century in Yangzhou, China. Early handheld muskets using matchlock or wheel lock mechanisms were limited by poor reliability and the risk of accidental discharge, which was improved somewhat by the introduction of the flintlock, though unintentional firing continued to be a serious ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dry Run (testing)
A dry run (or practice run) is a software testing process where the effects of a possible failure are intentionally mitigated. For example, an aerospace company may conduct a "dry run" test of a jet's new pilot ejection seat while the jet is parked on the ground, rather than while it is in flight. The usage of "dry run" in acceptance procedures (for example in factory acceptance testing) is meant as following: the factory, which is a subcontractor, must perform a complete test of the system it has to deliver before the actual acceptance by customer. Etymology The term dry run appears to have originated from fire departments in the U.S. In order to practice, they would carry out dispatches of the fire brigade where water was not pumped. A run with real fire and water was referred to as a wet run. The more general usage of the term seems to have arisen from widespread use by the United States Armed Forces during World War II. See also *Code review *Pilot experiment A pilot study, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossbow
A crossbow is a ranged weapon using an elastic launching device consisting of a bow-like assembly called a ''prod'', mounted horizontally on a main frame called a ''tiller'', which is hand-held in a similar fashion to the stock of a long firearm. Crossbows shoot arrow-like projectiles called '' bolts'' or ''quarrels''. A person who shoots crossbow is called a ''crossbowman'' or an '' arbalist'' (after the arbalest, a European crossbow variant used during the 12th century). Although crossbows and bows use the same launch principle, the difference is that an archer must maintain a bow's draw manually by pitching the bowstring with fingers, pulling it back with arm and back muscles and then holding that same form in order to aim (which distresses the body and demands significant physical strength and stamina); while a crossbow utilizes a locking mechanism to maintain the draw, limiting the shooter's exertion to only pulling the string into lock and then releasing the shot by d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compound Bow
In modern archery, a compound bow is a bow that uses a levering system, usually of cables and pulleys, to bend the limbs. In general, compound bows are widely used in target practice and hunting. The pulley/cam system grants the user a mechanical advantage, and so the limbs of a compound bow are much stiffer than those of a recurve bow or longbow. This rigidity makes the compound bow more energy-efficient than other bows, as less energy is dissipated in limb movement. The higher-rigidity, higher-technology construction also improves accuracy by reducing the bow's sensitivity to changes in temperature and humidity. The pulley/cam system also confers a benefit called "let-off." As the string is drawn back, the cams rotate. The cams are eccentric rather than round, and so their effective radius changes as they rotate. Each of a compound bow's two cams features two tracks: an inner track which connects to the opposite limb or opposite cam through cables, and an outer track throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastic Energy
Elastic energy is the mechanical potential energy stored in the configuration of a material or physical system as it is subjected to elastic deformation by work performed upon it. Elastic energy occurs when objects are impermanently compressed, stretched or generally deformed in any manner. Elasticity theory primarily develops formalisms for the mechanics of solid bodies and materials. (Note however, the work done by a stretched rubber band is not an example of elastic energy. It is an example of entropic elasticity.) The elastic potential energy equation is used in calculations of positions of mechanical equilibrium. The energy is potential as it will be converted into other forms of energy, such as kinetic energy and sound energy, when the object is allowed to return to its original shape (reformation) by its elasticity. U = \frac 1 2 k\, \Delta x^2 The essence of elasticity is reversibility. Forces applied to an elastic material transfer energy into the material wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bow And Arrow
The bow and arrow is a ranged weapon system consisting of an elastic launching device (bow) and long-shafted projectiles (arrows). Humans used bows and arrows for hunting and aggression long before recorded history, and the practice was common to many prehistoric cultures. They were important weapons of war from ancient history until the early modern period, where they were rendered increasingly obsolete by the development of the more powerful and accurate firearms. Today, bows and arrows are mostly used for hunting and sports. Archery is the art, practice, or skill of using bows to shoot arrows.Paterson ''Encyclopaedia of Archery'' p. 17 A person who shoots arrows with a bow is called a bowman or an archer. Someone who makes bows is known as a bowyer,Paterson ''Encyclopaedia of Archery'' p. 31 someone who makes arrows is a fletcher,Paterson ''Encyclopaedia of Archery'' p. 56 and someone who manufactures metal arrowheads is an arrowsmith.Paterson ''Encyclopaedia of Archer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archery
Archery is the sport, practice, or skill of using a bow to shoot arrows.Paterson ''Encyclopaedia of Archery'' p. 17 The word comes from the Latin ''arcus'', meaning bow. Historically, archery has been used for hunting and combat. In modern times, it is mainly a competitive sport and recreational activity. A person who practices archery is typically called an archer, bowman, or toxophilite. History Origins and ancient archery The oldest known evidence of the bow and arrow comes from South African sites such as Sibudu Cave, where the remains of bone and stone arrowheads have been found dating approximately 72,000 to 60,000 years ago.Backwell L, d'Errico F, Wadley L.(2008). Middle Stone Age bone tools from the Howiesons Poort layers, Sibudu Cave, South Africa. Journal of Archaeological Science, 35:1566–1580. Backwell L, Bradfield J, Carlson KJ, Jashashvili T, Wadley L, d'Errico F.(2018). The antiquity of bow-and-arrow technology: evidence from Middle Stone Age laye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chamber (weaponry)
In firearms, the chamber is the cavity at the back end of a breechloader's barrel or cylinder, where the cartridge is inserted before being fired. The rear opening of the chamber is the breech, and is sealed by the breechblock or the bolt. Function Rifles and pistols generally have a single chamber integral to their barrels, but revolvers have multiple chambers in their cylinder, and no chamber in their barrel. Thus, rifles and pistols can usually still be fired with the magazine removed as long as a cartridge is inserted into the chamber, while a revolver cannot be fired at all with its cylinder swung out. The act of ''chambering'' a cartridge means the insertion of a round into the chamber, either manually or through the action of the weapon, e.g., pump-action, lever-action, bolt action, or Autoloading operation generally in anticipation of firing the weapon, without need to "load" the weapon upon decision to use it (reducing the number of ''actions'' needed to di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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