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Walther PPQ
The Walther PPQ (, ''Polizeipistole Quick Defence'' / Police Pistol Quick Defence) is a semi-automatic pistol developed by the German company Carl Walther GmbH Sportwaffen of Ulm for law enforcement, security forces and the civilian shooting market as a development of the Walther P99. It is available in 9×19mm Parabellum, 9×21mm, .40 S&W, and .45 ACP chamberings. In 2021, Walther announced that they would be discontinuing the PPQ in favor of the new Walther PDP, or Performance Duty Pistol. Product evolution The Walther PPQ is not a true new design. It shares its engineering principles and main features with the Walther P99QA variant of the P99 pistol that was introduced in 2000. However, unlike the P99QA, which utilized a partially cocked striker (like a Glock), the PPQ utilizes a fully cocked striker. There were many other modifications made to the design that were not seen on the Walther P99QA, like the re-designed grip, trigger guard and slide with forward (big) serrati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semi-automatic Pistol
A semi-automatic pistol is a type of repeating single-chamber handgun ( pistol) that automatically cycles its action to insert the subsequent cartridge into the chamber (self-loading), but requires manual actuation of the trigger to actually discharge the following shot. As a result, only one round of ammunition is fired each time the trigger is pulled, as the pistol's fire control group disconnects the trigger mechanism from the firing pin/ striker until the trigger has been released and reset. Additional terms sometimes used as synonyms for a semi-automatic pistol are self-loading pistol, autopistol, autoloading pistol, and automatic pistol (E.G.: Automatic Colt Pistol). A semi-automatic pistol recycles part of the energy released by the propellant combustion to move its bolt, which is usually housed inside the slide. After a round of ammunition is fired, the spent cartridge casing is extracted and ejected as the slide/bolt moves rearwards under recoil, the hammer/s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Browning
John Moses Browning (January 23, 1855 – November 26, 1926) was an American firearm designer who developed many varieties of military and civilian firearms, cartridges, and gun mechanisms many of which are still in use around the world. He made his first firearm at age 13 in his father's gun shop and was awarded the first of his 128 firearm patents on October 7, 1879, at the age of 24. He is regarded as one of the most successful firearms designers of the 19th and 20th centuries and pioneered the development of modern repeating, semi-automatic, and automatic firearms. Browning influenced nearly all categories of firearms design, especially the autoloading of ammunition. He invented, or made significant improvements to, single-shot, lever-action, and pump-action rifles and shotguns. He developed the first reliable and compact autoloading pistols by inventing the telescoping bolt, then integrating the bolt and barrel shroud into what is known as the pistol slide. Browning's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proof Test
A proof test is a form of stress test to demonstrate the fitness of a load-bearing structure. An individual proof test may apply only to the unit tested, or to its design in general for mass-produced items. Such a structure is often subjected to loads above that expected in actual use, demonstrating safety and design margin. Proof testing is nominally a nondestructive test, particularly if both design margins and test levels are well-chosen. However, unit failures are by definition considered to have been destroyed for their originally-intended use and load levels. Proof tests may be performed before a new design or unit is allowed to enter service, or perform additional uses, or to verify that an existing unit is still functional as intended.Test intervals for in-service ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concealed Carry In The United States
Concealed carry, or carrying a concealed weapon (CCW), is the practice of carrying a weapon (such as a handgun) in public in a concealed manner, either on one's person or in close proximity. CCW is often practiced as a means of self-defense. Every state in the United States allows for concealed carry of a handgun either permitless or with a permit, although the difficulty in obtaining a permit varies per jurisdiction. There is conflicting evidence regarding the effect that concealed carry has on crime rates. A comprehensive 2004 literature review by the National Academy of Sciences concluded that there is no link between the existence of laws that allow concealed carry and crime rates. A 2020 review by the RAND Corporation concluded there was limited evidence that shall-issue concealed carry laws may increase violent crime overall, while there was inconclusive evidence for the effect of shall-issue laws on all individual types of violent crime. History The Second Amendment to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stainless Steel
Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corrosion resistance, resistance to corrosion results from the chromium, which forms a Passivation (chemistry), passive film that can protect the material and self-healing material, self-heal in the presence of oxygen. The alloy's properties, such as luster and resistance to corrosion, are useful in many applications. Stainless steel can be rolled into Sheet metal, sheets, plates, bars, wire, and tubing. These can be used in cookware, cutlery, surgical instruments, major appliances, vehicles, construction material in large buildings, industrial equipment (e.g., in paper mills, chemical plants, water treatment), and storage tanks and tankers for chemicals and food products. The biological cleanability of stainless steel is superior to both alumi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seawater
Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately of dissolved salts (predominantly sodium () and chloride () ions). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at ) because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about . The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was . Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measurement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rockwell Scale
The Rockwell scale is a hardness scale based on indentation hardness of a material. The Rockwell test measures the depth of penetration of an indenter under a large load (major load) compared to the penetration made by a preload (minor load). There are different scales, denoted by a single letter, that use different loads or indenters. The result is a dimensionless number noted as HRA, HRB, HRC, etc., where the last letter is the respective Rockwell scale. When testing metals, indentation hardness correlates linearly with tensile strength. History The differential depth hardness measurement was conceived in 1908 by Viennese professor Paul Ludwik in his book ''Die Kegelprobe'' (crudely, "the cone test"). The differential-depth method subtracted out the errors associated with the mechanical imperfections of the system, such as backlash and surface imperfections. The Brinell hardness test, invented in Sweden, was developed earlier – in 1900 – but it was slow, not use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitriding
Nitriding is a heat treating process that diffuses nitrogen into the surface of a metal to create a case-hardened surface. These processes are most commonly used on low-alloy steels. They are also used on titanium, aluminium and molybdenum. Typical applications include gears, crankshafts, camshafts, cam followers, valve parts, extruder screws, die-casting tools, forging dies, extrusion dies, firearm components, injectors and plastic-mold tools. Processes The processes are named after the medium used to donate. The three main methods used are: ''gas nitriding'', ''salt bath nitriding'', and ''plasma nitriding''. Gas nitriding In gas nitriding the donor is a nitrogen-rich gas, usually ammonia (NH3), which is why it is sometimes known as ''ammonia nitriding''. When ammonia comes into contact with the heated work piece it dissociates into nitrogen and hydrogen. The nitrogen then diffuses onto the surface of the material creating a nitride layer. This process has existed for nearly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tenifer
Ferritic nitrocarburizing or FNC, also known by the proprietary names Tenifer, Tufftride and Melonite as well as ARCOR,Other trade names include Tuffride/ Tuffrider, QPQ, Sulfinuz, Sursulf, Meli 1, and Nitride, among others is a range of proprietary case hardening processes that diffuse nitrogen and carbon into ferrous metals at sub- critical temperatures during a salt bath. Other methods of ferric nitrocarburizing include gaseous process such as Nitrotec and ion (plasma) ones. The processing temperature ranges from to , but usually occurs at . At this temperature steels and other ferrous alloys remain in the ferritic phase region. This allows for better control of the dimensional stability that would not be present in case hardening processes that occur when the alloy is transitioned into the austenitic phase.. There are four main classes of ferritic nitrocarburizing: ''gaseous'', ''salt bath'', ''ion'' or ''plasma'', and ''fluidized-bed''.. The process is used to improve thre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Applications
Many scientific, military, medical and commercial laser applications have been developed since the invention of the laser in 1958. The coherency, high monochromaticity, and ability to reach extremely high powers are all properties which allow for these specialized applications. Scientific In science, lasers are used in many ways, including: * A wide variety of interferometric techniques'' * Raman spectroscopy * Laser induced breakdown spectroscopy * Atmospheric ''remote sensing'' * Investigating nonlinear optics phenomena * Holographic techniques employing lasers also contribute to a number of measurement techniques. * Laser based lidar (LIght raDAR) technology has application in geology, seismology, remote sensing and atmospheric physics. * Lasers have been used aboard spacecraft such as in the Cassini-Huygens mission. * In astronomy, lasers have been used to create artificial ''laser guide stars'', used as reference objects for adaptive optics telescopes. Lasers may als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tactical Light
A tactical light is a flashlight used in conjunction with a firearm to aid low-light target identification, allowing the marksman, law enforcement officer or soldier to simultaneously aim a weapon and illuminate the target. Tactical lights can be handheld or mounted to the weapon with the light beam parallel to the bore. Tactical lights also serve a role as a method of non-lethal force, used to temporarily blind and disorient targets or, in the case of a large metal Maglite with D batteries, police can use the flashlight as a billy club. Features particularly associated with tactical lights include shock resistance, reliability, lightweight construction and powerful, long-lasting batteries, and high light intensity. Tactical lights may have optional filters to produce colored light, e.g., red, to not attract bugs, or may emit only infrared radiation for use with night vision equipment. A sighting laser may also be added to a weapon-mounted tactical light. Handheld lights Hand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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