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Open Sights
Iron sights are a system of physical alignment markers (usually made of metallic material) used as a sighting device to assist the accurate aiming of ranged weapons (such as a firearm, airgun, crossbow or even compound bow), or less commonly as a primitive finder sight for optical telescopes. The earliest sighting device, it relies completely on the viewer's naked eye (mostly under ambient lighting), and is distinctly different to optical sights such as telescopic sights, reflector (reflex) sights, holographic sights and laser sights, which make use of optical manipulation and/or active illumination, as well as the newer optoelectronics, which use digital imaging and even incorporate augmented reality. Iron sights are typically composed of two components mounted perpendicularly above the weapon's bore axis: a rear sight nearer (or ''proximally'') to the shooter's eye, and a front sight farther forward (or ''distally'') near the muzzle. During aiming, the shooter aligns his/ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties. Most optical phenomena can be accounted for by using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varmint Hunting
Varmint hunting or varminting is the practice of hunting vermin — generally small/medium-sized wild mammals or birds — as a means of pest control, rather than as games for food or trophy. The targeted animals are culled because they are considered economically harmful pests to agricultural crops, livestocks or properties; pathogen-carrying hosts/vectors that transmit cross-species/zoonotic diseases; or for population control as a mean of protecting other vulnerable species and ecosystems. The term "varminter" may refer to a ''varmint hunter'', or describe the hunting equipments (such as a varmint rifle) either specifically designed or coincidentally suitable for the practice of varmint hunting. Varmint hunters may hunt to exterminate a nuisance animal from their own property, to collect a bounty offered by another landowner or the government, or simply as a hobby. Targets of varmint hunting The term ''varmint'' is a US colloquial term for ''vermin'', though it refers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windage
Windage is a term used in aerodynamics, firearms ballistics, and automobiles. Usage Aerodynamics Windage is a force created on an object by friction when there is relative movement between air and the object. Windage loss is the reduction in efficiency due to windage forces. For example, electric motors are affected by friction between the rotor and air. Large alternators have significant losses due to windage. To reduce losses, hydrogen gas may be used, since it is less dense. There are two causes of windage: # The object is moving and being slowed by resistance from the air. # A wind is blowing, producing a force on the object. The term can refer to: * The effect of the force, for example the deflection of a missile or an aircraft by a cross wind. * The area and shape of the object that make it susceptible to friction, for example those parts of a boat that are exposed to the wind. Aerodynamic streamlining can be used to reduce windage. There is a hydrodynamic effect si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elevation (ballistics)
In ballistics, the elevation is the angle between the horizontal plane and the axial direction of the barrel of a gun, mortar or heavy artillery. Originally, elevation was a ''linear'' measure of how high the gunners had to physically lift the muzzle of a gun up from the gun carriage to compensate for projectile drop and hit targets at a certain distance. Until WWI Though early 20th-century firearms were relatively easy to fire, artillery was not. Before and during World War I, the only way to effectively fire artillery was plotting points on a plane. Most artillery units seldom employed their guns in small numbers. Instead of using pin-point artillery firing they used old means of " fire for effect" using artillery en masse. This tactic was employed successfully by past armies. By World War I, reasonably accurate artillery fire was possible even at long range requiring significant elevation. However, artillery tactics used in previous wars were carried on, and still had simil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sighting In
In ranged weapons such as firearms and artillery pieces, sighting in or sight-in is a preparatory or corrective calibration of the sights with the goal that the projectile (e.g. bullet or shell) may be placed at a predictable impact position within the sight picture. The principle of sighting-in is to shift the line of aim until it intersects the parabolic projectile trajectory at a designated point of reference, so when the gun is fired in the future (provided there is reliable precision) it will repeatably hit where it aims at identical distances of that designated point. Because when using a telescopic sight, the crosshair lines geometrically resemble the X- and Y-axis of the Cartesian coordinate system where the reticle center is analogous to the origin point ( i.e. coordinate ,0, the designated sighting-in point is known as a zero, and the act of sighting-in is therefore also called zeroing. A gunsight that remains true to its designated zero after repeated usage i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battle Rifle
A battle rifle is a service rifle chambered to fire a fully powered cartridge. The term "battle rifle" is a retronym created largely out of a need to better differentiate the intermediate cartridge, intermediate-powered assault rifles (e.g. the StG-44, AK-47, M16 rifle, M16, Steyr AUG, AUG) from full-powered rifles (e.g. the FG-42, AVS-36, FN FAL, and M14 rifle, M14, as well as the H&K G3 outside of sniping uses) as both classes of modern firearms have a similar appearance and share many of the same features such as magazine (firearms), detachable magazines, pistol grips, separate upper and lower receiver (firearms), receivers etc. Battle rifles were most prominent from the 1940s to the 1970s, when they were used as Service rifle, service rifles. While modern battle rifles largely resemble modern assault rifle designs, which replaced battle rifles in most roles, the term may also describe older military full-powered semi-automatic rifles such as the M1 Garand, SVT-40, Gewehr 41, Ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Handgun
A handgun is a short- barrelled gun, typically a firearm, that is designed to be usable with only one hand. It is distinguished from a long gun (i.e. rifle, shotgun or machine gun, etc.), which needs to be held by both hands and also braced against the shoulder to be used properly. The two most common types of handguns in modern times are revolvers and semi-automatic pistols, although other types such as derringers and machine pistols also see infrequent usage. Before commercial mass production, handguns were often considered a badge of office, comparable to a ceremonial sword. As they had limited utility and were more expensive than the long guns of the era, the few who could only afford to purchase them carried these handguns. However, in 1836, Samuel Colt patented the Colt Paterson, the first practical mass-produced revolver, which was capable of firing five shots in rapid succession and very quickly became a popular defensive weapon, giving rise to the saying, "God cre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long Gun
A long gun is a category of firearms with long barrels. In small arms, a ''long gun'' or longarm is generally designed to be held by both hands and braced against the shoulder, in contrast to a handgun, which can be fired being held with a single hand. In the context of cannons and mounted firearms, an artillery ''long gun'' would be contrasted with a field gun or howitzer. Small arms The actual length of the barrels of a long gun is subject to various laws in many jurisdictions, mainly concerning minimum length, sometimes as measured in a specific position or configuration. The National Firearms Act in the United States sets a minimum length of for rifle barrels and for shotgun barrels. Canada sets a minimum of for either. In addition, Canada sets a minimum fireable length for long guns with detachable or folding stocks . In the United States, the minimum length for long guns with detachable or folding stocks is with the stock in the extended position. Examples of various ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sightline
In architecture, sightlines are a particularly important consideration in the design of civic structures, such as a stage, arena, or monument. They determine the configuration of such items as theater and stadium design, road junction layout and urban planning. In cities such as London, construction within sightlines is restricted to protect the key views of famous landmarks Subjects that have a line of sight with one another are said to be intervisible, where intervisibility is the ability of viewers at separate places to see each other without any landform blocking their view. C-Value Good sightlines allow spectators to see all areas of a venue stage or field of play. To ensure this designers utilize the C-value, defined as the vertical distance from a spectator's eyes to sightline of the spectator directly behind. The C-value is determined in part by the rake, that is, the upward slope of the seating. The stadium bowl rake if based on consistent C-values will follow half ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muzzle (firearm)
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bore Axis
The bore axis of a firearm is the longitudinal axis through the geometric center of the gun barrel. In a rifled barrel, the projectile (bullet/ball, pellet or slug) will spin around the bore axis as it goes through the barrel. Boresighting is a process of placing one's line of sight down along the bore axis. Bore-to-sight distance The distance between the bore axis and the sight axis (the optical axis of a sighting device), also known as the ''sight height'', is an important factor to consider due to parallax principles. It is normally desirable to keep the sights of a firearm as close to the bore as possible, since a firearm with a large bore-to-sight distance will require more compensatory sight adjustment when shifting between shooting at different targets at close ranges (due to foreshortening). On the other hand, a firearm with a short bore-to-sight distance will need less sight adjustment when changing between targets at close ranges. At longer ranges the bore-to-s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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