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Driving Band
Russian 122 mm shrapnel shell, which has been fired, showing rifling marks on the copper driving band around its base and the steel bourrelet nearer the front A driving band or rotating band is a band of soft metal near the base of an artillery shell, often made of gilding metal, copper, or lead. When the shell is fired, the pressure of the propellant swages the metal into the rifling of the barrel and forms a gas seal; this seal prevents the gases from blowing past the shell and engages the barrel's rifling to spin-stabilize the shell. Purpose The rotating band has three essential functions: * Center the rear end of the projectile in the gun barrel. * Seal the bore to prevent burning powder gas from moving through the rifling grooves past the projectile. * Engage with the rifling of the barrel to spin the projectile and stabilize its flight. Characteristics The shell is stabilized for yaw in the barrel by a smaller bourrelet band near the front of the projectile. This b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HEAT
In thermodynamics, heat is energy in transfer between a thermodynamic system and its surroundings by such mechanisms as thermal conduction, electromagnetic radiation, and friction, which are microscopic in nature, involving sub-atomic, atomic, or molecular particles, or small surface irregularities, as distinct from the macroscopic modes of energy transfer, which are thermodynamic work and transfer of matter. For a closed system (transfer of matter excluded), the heat involved in a process is the difference in internal energy between the final and initial states of a system, after subtracting the work done in the process. For a closed system, this is the formulation of the first law of thermodynamics. Calorimetry is measurement of quantity of energy transferred as heat by its effect on the states of interacting bodies, for example, by the amount of ice melted or by change in temperature of a body. In the International System of Units (SI), the unit of measurement for he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sabot (firearms)
A sabot (, ) is a supportive device used in firearm/artillery ammunitions to fit/patch around a projectile, such as a bullet/slug or a flechette-like projectile (such as a kinetic energy penetrator), and keep it aligned in the center of the barrel when fired. It allows a narrower projectile with high sectional density to be fired through a barrel of much larger bore diameter with maximal accelerative transfer of kinetic energy. After leaving the muzzle, the sabot typically separates from the projectile in flight, diverting only a very small portion of the overall kinetic energy. The sabot component in projectile design is the relatively thin, tough and deformable seal known as a driving band or obturation ring needed to trap propellant gases behind a projectile, and also keep the projectile centered in the barrel, when the outer shell of the projectile is only slightly smaller in diameter than the caliber of the barrel. Driving bands and obturators are used to seal these fu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obturation
Obturation is the necessary barrel blockage or fit in a firearm or airgun created by a deformed soft projectile. A bullet or pellet made of soft material and often with a concave base will flare under the heat and pressure of firing, filling the bore and engaging the barrel's rifling. The mechanism by which an undersized soft-metal projectile enlarges to fill the barrel is, for hollow-base bullets, expansion from gas pressure within the base cavity and, for solid-base bullets, "upsetting"—the combined shortening and thickening that occurs when a malleable metal object is struck forcibly at one end. Obturation is achieved in shotgun shells (which have multiple pellets much smaller than the barrel bore) by placing a plastic wad or biodegradable card of the same diameter as the barrel between the propellant powder and the pellets. In a cartridge - such as a bullet or cased artillery shell - "obturation" is initiated by the action of a soft metallic cartridge case being pressed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Check
Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as oxygen) or from different atoms ( compounds such as carbon dioxide). A ''gas mixture'', such as air, contains a variety of pure gases. What distinguishes gases from liquids and solids is the vast separation of the individual gas particles. This separation can make some gases invisible to the human observer. The gaseous state of matter occurs between the liquid and plasma states, the latter of which provides the upper-temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention. High-density atomic gases super-cooled to very low temperatures are classified by their statistical behavior as either Bose gases or Fermi gases. For a comprehensive list ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cannelure
A cannelure is a groove or channel around ammunition, either bullets or cartridge cases. The cannelure may be pressed into or cast with the bullet or case. Function In the Minié ball the purpose of the cannelure is to hold a lubricant. Cannelures for this purpose are commonly called "grease grooves" or "lubrication (lube) grooves" or just "grooves" by bullet casters (see the glossary of firearms technical terminology maintained by SAAMI). The lubricant reduces metal fouling by lead that is rubbed off the projectile and onto the bore by friction. It also reduces the rate of bore fouling by black powder residue. In modern bullets, such as the 7.62 illustrated here, the cannelure is pressed into the circumference of the bullet to provide a strong purchase for the mouth of the cartridge case when it is crimped onto that cannelure. This is done to prevent the bullet from moving either forward or backward in the case. While bullet setback can be a problem with any self-loading gu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most abundant element in the Earth's crust, being mainly deposited by meteorites in its metallic state. Extracting usable metal from iron ores requires kilns or furnaces capable of reaching , about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BC and the use of iron tools and weapons began to displace copper alloys – in some regions, only around 1200 BC. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks in World War II, Tanks and Air warfare of World War II, aircraft played major roles, enabling the strategic bombing of cities and delivery of the Atomic bombings of Hiroshima and Nagasaki, first and only nuclear weapons ever used in war. World War II is the List of wars by death toll, deadliest conflict in history, causing World War II casualties, the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Allied-occupied Germany, Germany, Allied-occupied Austria, Austria, Occupation of Japan, Japan, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Full Metal Jacket Bullet
A full metal jacket (FMJ) bullet is a small-arms projectile consisting of a soft core (often lead) encased in an outer shell ("jacket") of harder metal, such as gilding metal, cupronickel, or, less commonly, a steel alloy. A bullet jacket usually allows higher muzzle velocity, muzzle velocities than bare lead without depositing significant amounts of metal in the Gun barrel, bore. It also prevents damage to bores from hard steel or armour-piercing ammunition, armor-piercing core materials. History Despite a widespread belief that the full metal jacket bullet was invented ca. 1882 by Swiss Colonel Eduard Rubin while he was working for the Swiss Federal Ammunition Factory and Research Center, in fact it was known already in the 1880s that the actual inventor was Prussian Major (later Lt.-Col.) (1835-1885), who came up with the idea either in 1875 or 1876. The use of full metal jacketing in military ammunition came about in part because of the need for improved feeding charac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rifle
A rifle is a long gun, long-barreled firearm designed for accurate shooting and higher stopping power, with a gun barrel, barrel that has a helical or spiralling pattern of grooves (rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with both hands and braced firmly against the shooter's shoulder via a buttstock for stability during shooting. Rifles are used in warfare, law enforcement, hunting and shooting sports, target shooting sports. The invention of rifling separated such firearms from the earlier smoothbore weapons (e.g., arquebuses, muskets, and other long guns), greatly elevating their accuracy and general effectiveness. The raised areas of a barrel's rifling are called ''lands''; they make contact with and exert torque on the projectile as it moves down the bore, imparting a spin. When the projectile leaves the barrel, this spin persists and lends gyroscopic stability to the projectile due to conservatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GAU-8 Avenger
The General Electric GAU-8/A Avenger is a 30 mm hydraulically driven seven-barrel Gatling-style autocannon that is primarily mounted in the United States Air Force's Fairchild Republic A-10 Thunderbolt II. Designed to destroy a wide variety of ground targets, the Avenger delivers 30mm rounds at a high rate of fire. The GAU-8/A is also used in the Dutch Goalkeeper CIWS ship weapon system, which provides defense against short-range threats such as highly maneuverable missiles, aircraft, and fast-maneuvering surface vessels. The GAU-8/A was designed by General Electric and has been produced by General Dynamics since 1977. autocannon Multiple-barrel firearms History The GAU-8 was created as a parallel program with the ''A-X'' (or Attack Experimental) competition that produced the A-10. The specification for the cannon was laid out in 1970, with General Electric and Philco-Ford offering competing designs. Both of the A-X prototypes, the YA-10 and the Northrop YA-9, were designe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GC-45 Howitzer
The GC-45 (''Gun, Canada, 45-Caliber (artillery), calibre'') is a 155 mm howitzer designed by Gerald Bull's Space Research Corporation (SRC) in the 1970s. Versions were produced by a number of companies during the 1980s, notably in Austria and South Africa. The most publicized use of the design was in Iraq, where the GHN-45 variant used by some Iraqi artillery units had a longer range than any coalition cannon systems. This initially caused considerable worry on the part of the allied forces in the Persian Gulf War. Design history The GC-45's general design followed several decades of work by Bull with fin-stabilized artillery shells, starting at the DRDC Valcartier, Canadian Armament Research and Development Establishment (CARDE) and later at Project HARP. In these efforts accuracy was not a huge concern, the objective was muzzle velocity, and the test articles were finned darts representing missiles, a low-cost alternative to wind tunnels. Yet with the removal of the rifli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
