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Sighting In
In ranged weapons such as firearms and artillery pieces, the act of sighting in or sight-in is a preparatory or corrective calibration of the sights with the goal of having the projectile (e.g. bullet or shell) placed on a predictable impact position in relation to 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benchrest Mauser Rifle
Benchrest shooting is a shooting sport discipline in which accuracy and precision, high-precision rifles are rested on a table or countertop, benchrather than being carried in the shooter's handswhile shooting at shooting target, paper or steel targets, hence the name "benchrest". Both the forearm (firearm component), forearm and buttstock of such a rifle are usually fully supported by bean bags, a bipod/monopod (front/rear) combination, and/or a specially designed fixture (tool), fixture device called shooting rest (which may be one- or two-piece depending on competition rules), so that the gun can remain stably pointing at the target without needing to be held by someone. When shooting, the shooter simply sits/stands comfortably behind the table/bench, operates the action (firearms), action and pulls the trigger (firearms), trigger, without needing to worry about carrying any weight of the gun. This is in contrast to other shooting disciplines, where the shooter has to bear at l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reticle
A reticle or reticule, also known as a graticule or crosshair, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the electronic visual display, screen of an oscilloscope, to provide frame of reference, measurement references during visual inspections. Today, engraved lines or embedded fibers may be replaced by a digital image superimposed on a screen or eyepiece. Both terms may be used to describe any set of patterns used for aiding visual measurements and calibrations, but in modern use ''reticle'' is most commonly used for weapon sight (device), sights, while ''graticule'' is more widely used for non-weapon measuring instruments such as oscilloscope#Graticule, oscilloscope display, astronomic telescopes, microscopes and microscope slide, slides, surveying instruments and other similar devices. There are many variations of reticle pattern; this article concerns its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bench Rest
Benchrest shooting is a shooting sport discipline in which high-precision rifles are rested on a table or benchrather than being carried in the shooter's handswhile shooting at paper or steel targets, hence the name "benchrest". Both the forearm and buttstock of such a rifle are usually fully supported by bean bags, a bipod/monopod (front/rear) combination, and/or a specially designed fixture device called shooting rest (which may be one- or two-piece depending on competition rules), so that the gun can remain stably pointing at the target without needing to be held by someone. When shooting, the shooter simply sits/stands comfortably behind the table/bench, operates the action and pulls the trigger, without needing to worry about carrying any weight of the gun. This is in contrast to other shooting disciplines, where the shooter has to bear at least part of the gun's weight while holding it steady to aim, even when using support devices such as bipods, tripods or shooting s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peep Sight
Iron sights are a system of physical alignment markers used as a sight (device), sighting device to assist the accurate aiming of ranged weapons such as firearms, airguns, crossbows, and Bow and arrow, bows, or less commonly as a primitive finder sight for optical telescopes. Iron sights, which are typically made of metal, are the earliest and simplest type of sighting device. Since iron sights neither magnify nor illuminate the target, they rely completely on the viewer's naked eye and the available light by which the target is visible. In this respect, iron sights are distinctly different from optical sight designs that employ optics, optical manipulation or active illumination, such as telescopic sights, reflector sight, reflector (reflex) sights, holographic weapon sight, holographic sights, and laser sight (firearms), laser sights. Iron sights are typically composed of two components mounted perpendicularly above the weapon's bore axis: a 'rear sight' nearer (or 'proximal') ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shooting Target
Shooting targets are objects in various forms and shapes that are used for pistol, rifle, shotgun and other shooting sports, as well as in darts, target archery, crossbow shooting and other non-firearm related sports. The center is often called the Bullseye (target), bullseye. Targets can for instance be made of paper, "self healing" rubber or steel target, steel. There are also electronic scoring system, electronic targets that electronically can provide the shooter with precise feedback of the shot placement. History Most targets used in shooting sports today are abstract figures of which origins often are not given much thought, but given the military and hunting origins that started most shooting disciplines it is not hard to understand that many of the targets at some point originally resembled either human opponents in a battle or animals in a hunting situation. For instance, the well known circular bullseye (target), bullseye target might originally have resembled a h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Sights
Iron sights are a system of physical alignment markers used as a sighting device to assist the accurate aiming of ranged weapons such as firearms, airguns, crossbows, and bows, or less commonly as a primitive finder sight for optical telescopes. Iron sights, which are typically made of metal, are the earliest and simplest type of sighting device. Since iron sights neither magnify nor illuminate the target, they rely completely on the viewer's naked eye and the available light by which the target is visible. In this respect, iron sights are distinctly different from optical sight designs that employ optical manipulation or active illumination, such as telescopic sights, reflector (reflex) sights, holographic sights, and laser sights. Iron sights are typically composed of two components mounted perpendicularly above the weapon's bore axis: a 'rear sight' nearer (or 'proximal') to the shooter's eye, and a 'front sight' farther forward (or 'distal') near the muzzle. During ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shotgun Shell
A shotgun cartridge, shotshell, or shell is a type of rimmed, cylindrical (straight-walled) ammunition used specifically in shotguns. It is typically loaded with numerous small, spherical sub-projectiles called shot. Shotguns typically use a smoothbore barrel with a tapered constriction at the muzzle to regulate the extent of scattering. Some cartridges contain a single solid projectile known as a slug (sometimes fired through a rifled slug barrel). The casing usually consists of a paper or plastic tube with a metallic base containing the primer. The shot charge is typically contained by wadding inside the case. The caliber of the cartridge is known as its gauge. The projectiles are traditionally made of lead, but other metals like steel, tungsten and bismuth are also used due to restrictions on lead, or for performance reasons such as achieving higher shot velocities by reducing the mass of the shot charge. Other unusual projectiles such as saboted flechettes, ru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minute Of Angle
A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a turn. The nautical mile (nmi) was originally defined as the arc length of a minute of latitude on a spherical Earth, so the actual Earth's circumference is very near . A minute of arc is of a radian. A second of arc, arcsecond (abbreviated as arcsec), or arc second, denoted by the symbol , is a unit of angular measurement equal to of a minute of arc, of a degree, of a turn, and (about ) of a radian. These units originated in Babylonian astronomy as sexagesimal (base 60) subdivisions of the degree; they are used in fields that involve very small angles, such as astronomy, optometry, ophthalmology, optics, navigation, land surveying, and marksmanship. To express even smaller angles, standard SI prefixes can be employed; the milliarcsec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sample Size Determination
Sample size determination or estimation is the act of choosing the number of observations or replicates to include in a statistical sample. The sample size is an important feature of any empirical study in which the goal is to make inferences about a population from a sample. In practice, the sample size used in a study is usually determined based on the cost, time, or convenience of collecting the data, and the need for it to offer sufficient statistical power. In complex studies, different sample sizes may be allocated, such as in stratified surveys or experimental designs with multiple treatment groups. In a census, data is sought for an entire population, hence the intended sample size is equal to the population. In experimental design, where a study may be divided into different treatment groups, there may be different sample sizes for each group. Sample sizes may be chosen in several ways: *using experience – small samples, though sometimes unavoidable, can result in wid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mann Rest
Franklin Weston Mann (July 24, 1856 – November 14, 1916) was an American physician and inventor remembered as author of the pioneering ballistics text entitled ''The Bullet's Flight from Powder to Target: The Internal and External Ballistics of Small Arms; a Study of Rifle Shooting with the Personal Element Excluded, Disclosing the Cause of the Error at Target''.Sipe, Warren "Dr. Mann: Father of Ballistic Science" in ''Guns'' November 1960 pp. 28–30,58&60 Early life Mann was youngest of six children born in Norfolk, Massachusetts to Levi and Lydia (Ware) Mann. He grew up on a New England farm and started shooting at the age of twelve. He was intrigued by causes of dispersion of bullets fired at a single point of aim. He graduated from Cornell University with a Bachelor of Science degree in 1878 and from Boston University School of Medicine as a Doctor of Medicine. He worked four years as a general practitioner including obstetrics while running a shop where he sharpene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geometric Center
In mathematics and physics, the centroid, also known as geometric center or center of figure, of a plane figure or solid figure is the arithmetic mean position of all the points in the figure. The same definition extends to any object in n-dimensional Euclidean space. In geometry, one often assumes uniform mass density, in which case the ''barycenter'' or ''center of mass'' coincides with the centroid. Informally, it can be understood as the point at which a cutout of the shape (with uniformly distributed mass) could be perfectly balanced on the tip of a pin. In physics, if variations in gravity are considered, then a ''center of gravity'' can be defined as the weighted mean of all points weighted by their specific weight. In geography, the centroid of a radial projection of a region of the Earth's surface to sea level is the region's geographical center. History The term "centroid" was coined in 1814. It is used as a substitute for the older terms "center of gravity" and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gun Barrel
A gun barrel is a crucial part of gun-type weapons such as small arms, 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 (firearms), muzzle) at a high velocity. The hollow interior of the barrel is called the bore, and the diameter of the bore is called its calibre, 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. History Gun barrels are usually made of some type of metal or Alloy, metal alloy. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
