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Chamber Pressure
Within firearms, chamber pressure is the pressure exerted by a cartridge case's outside walls on the inside of a firearm's chamber when the cartridge is fired. The SI unit for chamber pressure is the megapascal (MPa), while the American SAAMI uses the pound per square inch (psi, symbol lbf/in2) and the European CIP uses bar (1 bar is equal to 0.1 MPa). Regardless of pressure unit used, the measuring procedure varies between CIP method, SAAMI method, and NATO EPVAT. The chamber pressures are measured to different standards thus can not be directly compared. Chamber pressures have also historically been recorded in copper units of pressure (which for example can be denoted psi CUP, bar CUP, or MPa CUP) or lead units of pressure (LUP). Overview When the firing pin in a firearm strikes the primer, it ignites the powder inside the case, igniting the powder causing obturation that generates a large amount of pressure, often exceeding 50,000 PSI (344.7 MPa). This pressure in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chamber (firearms)
The chamber of a firearm is the cavity at the back end of a breechloading weapon's barrel or cylinder, where the ammunition is inserted before being fired. The rear opening of the chamber is the breech, and is sealed by the breechblock or the bolt. Function The act of ''chambering'' a cartridge means the insertion of a round into the chamber, either manually or through the action of the weapon, e.g., pump-action, lever-action, bolt action, or autoloading operation generally in anticipation of firing the weapon, without need to "load" the weapon upon decision to use it (reducing the number of ''actions'' needed to discharge). Automatic and single-shot pistols (such as Derringers), rifles, and shotguns generally have a single chamber integral to their barrels, but revolvers have multiple chambers in their cylinder, and no chamber in their barrel. Thus, pistols, rifles, and shotguns can usually still be fired with the magazine removed as long as a cartridge is inser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megapascal
The pascal (symbol: Pa) is the unit of pressure in the International System of Units (SI). It is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is an SI coherent derived unit defined as one newton per square metre (N/m2). It is also equivalent to 10 barye (10 Ba) in the CGS system. Common multiple units of the pascal are the hectopascal (1 hPa = 100 Pa), which is equal to one millibar, and the kilopascal (1 kPa = 1000 Pa), which is equal to one centibar. The unit of measurement called '' standard atmosphere (atm)'' is defined as . Meteorological observations typically report atmospheric pressure in hectopascals per the recommendation of the World Meteorological Organization, thus a standard atmosphere (atm) or typical sea-level air pressure is about 1013 hPa. Reports in the United States typically use inches of mercury or millibars (hectopascals). In Canada, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sporting Arms And Ammunition Manufacturers' Institute
The Sporting Arms and Ammunition Manufacturers' Institute (SAAMI, pronounced "Sammy") is an association of American manufacturers of firearms, ammunition, and components. SAAMI is an accredited standards developer that publishes several American National Standards that provide safety, reliability, and interchangeability standards for commercial manufacturers of firearms, ammunition, and components. In addition, SAAMI publishes information on the safe and responsible transportation, storage, and use of those products. History The origins of SAAMI date back to World War I and the Society of American Manufacturers of Small Arms and Ammunition (SAMSAA). In 1913, the US War Department encouraged the firearms and ammunition industry to establish an organization to share new technology and establish common standards for small arms and ammunition. SAMSAA was officially formed in 1918, however became inactive by the early 1920s. By the mid-1920s, the United States was still su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pound Per Square Inch
The pound per square inch (abbreviation: psi) or, more accurately, pound-force per square inch (symbol: lbf/in2), is a unit of measurement of pressure or of stress based on avoirdupois units and used primarily in the United States. It is the pressure resulting from a force with magnitude of one pound-force applied to an area of one square inch. In SI units, 1 psi is approximately . The pound per square inch absolute (psia) is used to make it clear that the pressure is relative to a vacuum rather than the ambient atmospheric pressure. Since atmospheric pressure at sea level is around , this will be added to any pressure reading made in air at sea level. The converse is pound per square inch gauge (psig), indicating that the pressure is relative to atmospheric pressure. For example, a bicycle tire pumped up to 65 psig in a local atmospheric pressure at sea level (14.7 psi) will have a pressure of 79.7 psia (14.7 psi + 65 psi). When gauge pressure is referenced to som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pound (force)
The pound of force or pound-force (symbol: lbf, sometimes lbf,) is a Units of measurement, unit of force used in some System of measurement, systems of measurement, including English Engineering units and the foot–pound–second system. Pound-force should not be confused with pound (mass), pound-mass (lb), often simply called "pound", which is a unit of mass; nor should these be confused with foot-pound (ft⋅lbf), a unit of energy (physics), energy, or pound-foot (lbf⋅ft), a unit of torque. Definitions The pound-force is equal to the gravitational force exerted on a mass of one Pound (mass)#Avoirdupois pound, avoirdupois pound on the surface of Earth. Since the 18th century, the unit has been used in low-precision measurements, for which small changes in Gravity of Earth, Earth's gravity (which varies from equator to pole by up to half a percent) can safely be neglected. The 20th century, however, brought the need for a more precise definition, requiring a standardized ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commission Internationale Permanente Pour L'épreuve Des Armes à Feu Portatives
The Commission internationale permanente pour l'épreuve des armes à feu portatives (English: ''Permanent International Commission for the Proof of Small Arms''), commonly abbreviated C.I.P., is an international organisation which sets standards for safety testing of firearms. (The word ''portatives'' ("portable") in the name refers to the fact the C.I.P. tests small arms almost exclusively; it is ordinarily omitted from the English translation of the name.) As of 2015, its members are the national governments of 14 countries, of which 11 are European Union member states. The C.I.P. safeguards that all firearms and ammunition sold to civilian purchasers in member states are safe for the users. To achieve this, all such firearms are first proof tested at C.I.P. accredited Proof Houses. The same applies for cartridges; at regular intervals, cartridges are tested against the C.I.P. pressure specifications at the ammunition manufacturing plants and at C.I.P. accredited Proof Houses. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bar (unit)
The bar is a metric unit of pressure defined as 100,000 Pa (100 kPa), though not part of the International System of Units (SI). A pressure of 1 bar is slightly less than the current average atmospheric pressure on Earth at sea level (approximately 1.013 bar). By the barometric formula, 1 bar is roughly the atmospheric pressure on Earth at an altitude of 111 metres at 15 °C. The bar and the millibar were introduced by the Norwegian meteorologist Vilhelm Bjerknes, who was a founder of the modern practice of weather forecasting, with the bar defined as one megadyne per square centimetre. The SI brochure, despite previously mentioning the bar, now omits any mention of it.. The bar has been legally recognised in countries of the European Union since 2004. British Standard BS 350:2004 ''Conversion Factors for Units''. The US National Institute of Standards and Technology (NIST) deprecates its use except for "limited use in meteorology" and lists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NATO EPVAT Testing
NATO EPVAT testing is one of the three recognized classes of procedures used in the world to control the safety and quality of firearms ammunition. Beside this, there are also the ''Commission internationale permanente pour l'épreuve des armes à feu portatives'' (C.I.P.) class of procedures and the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) class of procedures. EPVAT Testing is described in unclassified documents by NATO, more precisely by the AC/225 Army Armaments Group (NAAG). It was accepted as NATO Standardization Agreement STANAG 4823 and Allied Engineering Publication 97 (AEP-97) in November 2020. EPVAT is an abbreviation for "Electronic Pressure, Velocity and Action Time" (French "Pression électronique, vitesse et durée d'action"). Action Time here means the (short amount of) time required between the ignition of the primer and the projectile leaving the barrel. This is a comprehensive procedure for testing ammunition using state-of-the-art instrum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper Units Of Pressure
Copper units of pressure or CUP, and the related lead units of pressure or LUP, are terms applied to pressure measurements used in the field of internal ballistics for the estimation of chamber pressures in firearms. These terms were adopted by convention to indicate that the pressure values were measured by copper crusher and lead crusher gauges respectively. In recent years, they have been replaced by the adoption of more modern piezoelectric pressure gauges that more accurately measure chamber pressures and generally give significantly higher pressure values. This nomenclature was adopted to avoid confusion and the potentially dangerous interchange of pressure values and standards made by different types of pressure gauges. For example, it makes little sense to describe a maximum pressure as 300 MPa, and in case the pressure has been measured according to the CUP procedure it should be denoted as 300 MPa (CUP). Pressure is a fundamental physical parameter that is defined as forc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piezoelectricity
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The piezoelectric effect results from the linear electromechanical interaction between the mechanical and electrical states in crystalline materials with no inversion symmetry. The piezoelectric effect is a reversible process: materials exhibiting the piezoelectric effect also exhibit the reverse piezoelectric effect, the internal generation of a mechanical strain resulting from an applied electric field. For example, lead zirconate titanate crystals will generate measurable piezoelectricity when their static structure is deformed by about 0.1% of the original dimension. Conversely, those same crystals will change about 0.1% of their static dimension when an external electric field is applied. The inverse piezoelectric effect is used in the pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strain Gauge
A strain gauge (also spelled strain gage) is a device used to measure Deformation (mechanics)#Strain, strain on an object. Invented by Edward E. Simmons and Arthur C. Ruge in 1938, the most common type of strain gauge consists of an Electrical insulation, insulating flexible backing which supports a metallic foil pattern. The gauge is attached to the object by a suitable adhesive, such as cyanoacrylate. As the object is deformed, the foil is deformed, causing its electrical resistance to change. This resistance change, usually measured using a Wheatstone bridge, is related to the strain by the quantity known as the gauge factor. History Edward E. Simmons and Professor Arthur C. Ruge independently invented the strain gauge. Simmons was involved in a research project by Dätwyler and Clark at Caltech between 1936 and 1938. They researched the stress-strain behavior of metals under shock loads. Simmons came up with an original way to measure the force introduced into the sample b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adiabatic Process
An adiabatic process (''adiabatic'' ) is a type of thermodynamic process that occurs without transferring heat between the thermodynamic system and its Environment (systems), environment. Unlike an isothermal process, an adiabatic process transfers energy to the surroundings only as Work (thermodynamics), work and/or mass flow.. A translation may be founhere. Also a mostly reliabltranslation is to be foundin As a key concept in thermodynamics, the adiabatic process supports the theory that explains the first law of thermodynamics. The opposite term to "adiabatic" is ''diabatic''. Some chemical and physical processes occur too rapidly for energy to enter or leave the system as heat, allowing a convenient "adiabatic approximation".Bailyn, M. (1994), pp. 52–53. For example, the adiabatic flame temperature uses this approximation to calculate the upper limit of fire, flame temperature by assuming combustion loses no heat to its surroundings. In meteorology, adiabatic expansion an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
