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Two years later, in 1965, Remington Arms adopted the .22-250, added "Remington" to the name and chambered their Model 700 and 40 XB match rifles for the cartridge along with a line of commercial ammunition, thus establishing its commercial specification. [6] The .22-250 was the first non-Weatherby caliber offered in the unique Weatherby Mark V ...
A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen who developed the chart in 1862 as a measurement tool for the acuity formula developed by his professor Franciscus Cornelius Donders .
An example of the Landolt C eye chart (also known as the Japanese eye chart). Numerous types of eye charts exist and are used in various situations. For example, the Snellen chart is designed for use at 6 meters or 20 feet, and is thus appropriate for testing distance vision, while the ETDRS chart is designed for use at 4 meters. [16]
Near visual acuity or near vision is a measure of how clearly a person can see nearby small objects or letters.Visual acuity in general usually refers clarity of distance vision, and is measured using eye charts like Snellen chart, LogMAR chart etc. Near vision is usually measured and recorded using a printed hand-held card containing different sized paragraphs, words, letters or symbols.
Sighting in a firearm is an important test of the ability of the firearm user to hit anticipated targets with available ammunition. Pictures or silhouettes of intended targets are less suitable for sighting in than high contrast shapes compatible with the type of sights on the firearm. Contrasting circles are commonly used as sighting in ...
Iron sight included on some models. The Weatherby Varmintmaster is a lighter quicker-handling version of the Weatherby Mark V . It was first offered for sale in 1963 in two barrel lengths: a 24-inch standard weight and 26-inch heavy weight.
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.
As in any other collimator sight, the user does not actually look through the sight but instead keeps the collimated (infinity) image of the illuminated part of the reticle in focus with the dominant eye while the other eye views the entire field of view to acquire the target. In this both-eyes-open technique the brain superimposes the aiming ...