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5.45×39mm Assault Rifles
The 5.45×39mm cartridge is a rimless bottlenecked intermediate cartridge. It was introduced into service in 1974 by the Soviet Union for use with the new AK-74. The 5.45×39mm gradually supplemented and then largely replaced the 7.62×39mm cartridge in Soviet and Warsaw Pact service as the primary military service rifle cartridge. History The 5.45×39mm cartridge was developed in the early 1970s by a group of Soviet designers and engineers under the direction of M. Sabelnikov. Further group members were: L. I. Bulavsky, B. B. Semin, M. E. Fedorov, P. F. Sazonov, V. Volkov, V. A. Nikolaev, E. E. Zimin and P. S. Korolev. The 5.45×39mm couples a sensible case volume (1.75 ml) to bore area (23.99 mm2/0.2399 cm2) ratio with ample space for loading relatively long slender projectiles that can provide good aerodynamic efficiency and external ballistic performance for the projectile diameter. The 5.45×39mm is an example of an international tendency towards relative ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national republics; in practice, both its government and its economy were highly centralized until its final years. It was a one-party state governed by the Communist Party of the Soviet Union, with the city of Moscow serving as its capital as well as that of its largest and most populous republic: the Russian SFSR. Other major cities included Leningrad (Russian SFSR), Kiev (Ukrainian SSR), Minsk ( Byelorussian SSR), Tashkent (Uzbek SSR), Alma-Ata (Kazakh SSR), and Novosibirsk (Russian SFSR). It was the largest country in the world, covering over and spanning eleven time zones. The country's roots lay in the October Revolution of 1917, when the Bolsheviks, under the leadership of Vladimir Lenin, overthrew the Russian Provisional Government ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartridge (firearms)
A cartridge or a round is a type of pre-assembled firearm ammunition packaging a projectile (bullet, shot, or slug), a propellant substance (usually either smokeless powder or black powder) and an ignition device (primer) within a metallic, paper, or plastic case that is precisely made to fit within the barrel chamber of a breechloading gun, for the practical purpose of convenient transportation and handling during shooting. Although in popular usage the term "bullet" is often informally used to refer to a complete cartridge, it is correctly used only to refer to the projectile. Cartridges can be categorized by the type of their primers – a small charge of an impact- or electric-sensitive chemical mixture that is located: at the center of the case head (centerfire); inside the rim ( rimfire); inside the walls on the fold of the case base that is shaped like a cup (cupfire, now obsolete); in a sideways projection that is shaped like a pin (pinfire, now obsolete); or a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drag (physics)
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, the drag force depends on velocity. Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of drag is viscous friction, turbulent drag is independent of viscosity. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid's path. Examples Examples of drag include the component of the net aerodynamic or hydrodynamic force acting opposite to the di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is toxic, even in small amounts, especially to children. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gilding Metal
Gilding metal is a form of brass (an alloy of copper and zinc) with a much higher copper content than zinc content. Exact figures range from 95% copper and 5% zinc to “8 parts copper to 1 of zinc” (11% zinc) in British Army Dress Regulations. Gilding metal is used for various purposes, including the jackets of bullets, driving bands on some artillery shells, as well as enameled badges and other jewellery. The sheet is widely used for craft metalworking by hammer working. It is also used particularly as a lower-cost training material for silversmiths. Starting in 1944, shell casings made of gilding metal were melted down by the United States Mint to be made into pennies. These pennies replaced the less popular steel cent of 1943, and the pennies of this composition were produced until 1946. Gilding metal was also used for the "bronze" Olympic medal at the 2020 Summer Olympics The , officially the and also known as , was an international multi-sport event held from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Recoil
Free recoil is a vernacular term or jargon for recoil energy of a firearm not supported from behind. Free recoil denotes the translational kinetic energy (''Et'') imparted to the shooter of a small arm when discharged and is expressed in joules (J), or foot-pound force (ft·lb''f'') for non-SI units of measure. More generally, the term refers to the recoil of a free-standing firearm, in contrast to a firearm securely bolted to or braced by a massive mount or wall. Free recoil should not be confused with recoil: * Free recoil is the given name for translational kinetic energy transmitted from a small arm to a shooter. * Recoil is a name given for conservation of momentum as it generally applies to an everyday event. Free recoil and firearms Free recoil, sometimes called ''recoil energy'', is a byproduct of the propulsive force from the powder charge held within a firearm chamber (metallic cartridge firearm) or breech (gunpowder firearm). The physical event of free recoil occurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolt Thrust
Bolt thrust or breech pressure is a term used in internal ballistics and firearms (whether small arms or artillery) that describes the amount of rearward force exerted by the propellant gases on the bolt or breech of a firearm action or breech when a projectile is fired. The applied force has both magnitude and direction, making it a vector quantity. Bolt thrust is an important factor in weapons design. The greater the bolt thrust, the stronger the locking mechanism has to be to withstand it. Assuming equal engineering solutions and material adding strength to a locking mechanism causes an increase in weight and size of locking mechanism components. Bolt thrust is not a measure to determine the amount of recoil or free recoil. Calculating bolt thrust With a basic calculation the bolt thrust produced by a particular firearms cartridge can be calculated fairly accurately. Formula :\vec_ = P_ \cdot A_. where: *''Fbolt'' = the amount of bolt thrust *''Pmax'' = the maximum (peak) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point-blank Range
Point-blank range is any distance over which a certain firearm can hit a target without the need to compensate for bullet drop, and can be adjusted over a wide range of distances by sighting in the firearm. If the bullet leaves the barrel parallel to the sight, the bullet, like any object in flight, is pulled downwards by gravity, so for distant targets, the shooter must point the firearm above the target to compensate. But if the target is close enough, bullet drop will be negligible so the shooter can aim the gun straight at the target. If the sights are set so that the barrel has a small upward tilt, the bullet starts by rising and later drops. This results in a weapon that hits too low for very close targets, too high for intermediate targets, too low for very far targets, and point blank at two distances in between. For a .270 Winchester, as an example, the bullet first crosses the line of sight at about 23 metres (25 yards) as it is rising and has a maximum impact above th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overbore
Overbore cartridges are those with a relatively large case volume or case capacity, coupled with a relatively small diameter bullet. The case volume or case capacity and barrel bore area can be mathematically related to obtain a case volume to bore area ratio in metric or imperial units. = \frac where: * Volume_ = the cartridge case internal volume or case capacity (in ml or (for non-metric users) grains of water) * Area_ = barrel bore cross section area (in cm2 or in2) The higher the Oratio result, the more overbore a cartridge will be. As the ratio is expressed in units of length, relatively high Oratio is a good predictor of suitability for relatively long barreled guns. Oratio is also used to predict barrel life in cartridges of the same caliber, but not of different calibres, since the ratio is an extensive quantity that does not correlate to temperature or pressure (e.g. a .50 cal straight cartridge may have the same overbore as a highly necked down .17 cal cartridge). Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparison Of Cold War Ammunition Rotated
Comparison or comparing is the act of evaluating two or more things by determining the relevant, comparable characteristics of each thing, and then determining which characteristics of each are similar to the other, which are different, and to what degree. Where characteristics are different, the differences may then be evaluated to determine which thing is best suited for a particular purpose. The description of similarities and differences found between the two things is also called a comparison. Comparison can take many distinct forms, varying by field: To compare things, they must have characteristics that are similar enough in relevant ways to merit comparison. If two things are too different to compare in a useful way, an attempt to compare them is colloquially referred to in English as "comparing apples and oranges." Comparison is widely used in society, in science and in the arts. General usage Comparison is a natural activity, which even animals engage in when deci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Service Rifle
A service rifle (or standard-issue rifle) is a rifle a military issues to regular infantry. In modern militaries, this is typically a versatile and rugged battle rifle, assault rifle, or carbine suitable for use in nearly all environments. Most militaries also have service pistols or sidearms to accompany their service rifles. History Firearms with rifled barrels existed long before the 19th century but did not become widely used before the end of the American Civil War. Thus, rifles in the early 19th century were for specialist marksmen only, whilst ordinary infantry were issued less accurate smoothbore muskets which had a higher rate of fire, with bore diameters as high as 19 mm (0.75 inch). Early "service rifles" of the 1840s, such as the Prussian Dreyse needle gun (1841) and the Swiss Infanteriegewehr Modell 1842, were technically still muskets. Ordnance rifles were introduced in the 1860s, with the French Chassepot (1866) and the Swiss Peabody ''Gewehr Mode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
