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Encyclopedia > Internal ballistics

Internal ballistics, a subfield of ballistics, is the study of a projectile's behavior from the time its propellant's igniter is initiated until it exits the gun barrel. The study of internal ballistics is important to designers and users of firearms of all types, from small-bore Olympic rifles and pistols, to high-tech artillery. Ballistics (gr. ... A projectile is any object sent through space by the application of a force. ... A propellant is a material that is used to move an object by applying a motive force. ... This article does not cite its references or sources. ... Designer is a broad term for a person who designs any of a variety of things. ... The five Olympic rings were designed in 1913, adopted in 1914 and debuted at the Games at Antwerp, 1920. ... It has been suggested that Break action be merged into this article or section. ... A Browning 9 millimeter Hi-Power Ordnance pistol of the French Navy, 19th century, using a Percussion cap mechanism Derringers were small and easily hidden. ... Artillery with Gabion fortification Cannons on display at Fort Point Continental Artillery crew from the American Revolution Firing of an 18-pound gun, Louis-Philippe Crepin, (1772 – 1851) A forge-welded Iron Cannon in Thanjavur, Tamil Nadu. ...

Contents

Ignition

Priming methods

The first step to firing a firearm of any sort is igniting the propellant. The earliest firearms were cannons, which were simple closed tubes. There was a small aperture, the "touchhole", drilled in the closed end of the tube, leading down to the main powder charge. This hole was filled with finely ground powder, which was then ignited with a hot ember or torch. With the advent of hand-held firearms, this became an undesirable way of firing a gun. Holding a burning stick, while trying to carefully pour a charge of black powder down a barrel, is dangerous, and trying to hold the gun with one hand while simultaneously aiming at the target and looking for the touchhole was not conducive to any degree of accuracy. A small cannon on a carriage, Bucharest. ... Wikipedia does not have an article with this exact name. ... A burning torch, discarded on the road in the wake of the Lewes Bonfire Night celebrations. ...


External priming

Matchlock: The first attempt to make the process of firing a small arm easier was the "matchlock". The matchlock incorporated a "lock" (so called, because of its resemblance to door locks of the day) that was actuated by a trigger. The lock was a simple lever which pivoted, when pulled, and lowered the match down to the touchhole. The match was a slow burning fuse made of plant fibers that were soaked in a solution of nitrates, charcoal, and sulphur, and dried. This was ignited before the gun might be needed, and it would slowly burn, keeping a hot ember at the burning end. After the gun was loaded, and the touchhole primed with powder, the burning tip of the match was positioned, so that the lock would bring it into contact with the touchhole. To fire the gun, it was aimed, and the trigger pulled. This brought the match down to the touchhole, igniting the powder. The slow burning match could be kept going, with careful attention, for long periods of time, and the use of the lock mechanism made accurate fire (within the limits of the gun) possible. A US Army 45 Colt. ... A burning match A match is a consumable tool for producing fire under controlled circumstances on demand. ... In an explosive device, a fuse (or fuze) is the part of the device that causes it to function. ... Nitrates are the salts of nitric acid. ... Charcoal is the blackish residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. ... For the chemical element see: sulfur. ... A gun is a common name given to a device that fires high-velocity projectiles. ...


Wheel-lock: The next revolution in ignition technology was the "wheel-lock". It used a spring-loaded, serrated steel wheel which rubbed against a piece of iron pyrite. There was a key which was used to wind the wheel, and put the spring under tension. Once tensioned, the wheel was held in place by a trigger. When the trigger was pulled, the serrated edge of the steel rubbed against the pyrite, generating sparks. These sparks were directed into a pan, called the "flashpan", filled with loose powder which lead into the touchhole. The flashpan was usually covered by a spring-loaded cover that would slide out of the way when the trigger was pulled, exposing the powder to the sparks. The wheel-lock was a major innovation — since it did not rely on burning material as a source of heat, it could be loaded, and kept loaded for extended periods of time. The covered flashpan also gave the gun some ability to withstand bad weather. Wind, rain, and wet weather would render a matchlock useless, but a wheel-lock that was loaded, and waterproofed with a bit of grease around the flashpan, could be fired under most conditions. 1 saw-like shape, consisting in a series of sharp peeks/teeth resembling triangles (the verteces, not the edges) Immagine a series of triangles layed on their edge and connected at that edges vertices, the remaning vertices (the non-connected ones) make-up the serration. ... The steel cable of a colliery winding tower. ... The force bearing on the axle has an eccentricity e with the point of contact to the rolling surface and exerts a moment about the contact point A wheel is a circular device capable of rotating on its axis, facilitating movement or transportation or performing labour in machines. ... The mineral pyrite, or iron pyrite, is iron disulfide, FeS2. ... Look up Spark in Wiktionary, the free dictionary. ... In physics, heat, symbolized by Q, is defined as transfer of thermal energy [1] Generally, heat is a form of energy transfer associated with the different motions of atoms, molecules and other particles that comprise matter when it is hot and when it is cold. ... Grease is a lubricant of higher initial viscosity than oil, consisting originally of a calcium, sodium or lithium soap jelly emulsified with mineral oil. ...


Flintlock: The wheel-lock enjoyed only a brief period of popularity before being superseded by a simpler, more robust design. The "flintlock", like the wheel-lock, used a flashpan and a spark to ignite the powder. As the name implies, the flintlock used flint, rather than iron pyrite. The flint was held in a spring-loaded arm, called the "cock". The cock rotated through about a 90 degree arc, and was held in the tensioned, or "cocked" position by a trigger. Usually, flintlocks would lock the cock in two positions. The "half-cock" position held the cock halfway back, and used a deep notch, so that pulling the trigger would not release the cock. This was a safety position, used when loading, and when storing or carrying a loaded flintlock. The "full-cock" position held the cock all the way back, and was the position from which the gun was fired. The "frizzen" was the other half of the flintlock ignition system. It served as both a flashpan cover, and a steel striking surface for the flint. The frizzen was hinged, and spring-loaded, so that it would lock in the open or closed position. When closed, the striking surface was positioned so that the flint would strike at the proper angle to generate a spark. The striking flint would also open the frizzen, exposing the flashpan to the spark. The flintlock mechanism was simpler, and stronger than the wheel-lock, and the flint and steel provided a good, reliable source of ignition. The flintlock remained in military service for over 200 years, and flintlocks are still made today for historical re-enactments, and for hunters who enjoy the additional challenge that the flintlock provides. A flint nodule from the Onondaga limestone layer, Buffalo, New York. ... Notch can refer to: a mountain pass Notch signaling This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... The frizzen is a curved plate of steel used in flintlock firearms. ...


Caplock: The next major leap in ignition technology was the invention of the chemical primer, or "cap", and the mechanism which used it, called the "caplock". The caplock appeared just before the American Civil War, and was quickly adopted by both sides as it was even simpler and more reliable than the flintlock. The main reason the caplock was so quickly adopted was its similarity to the flintlock. The flashpan and frizzen were removed, and replaced by a "nipple" which the cap fit onto. The cock was replaced by a "hammer", which also had half-cock and full-cock positions for the same reasons. When fired, the hammer would hit the cap, crushing it onto the nipple. The percussion cap was a thin metal cup that had in it, a small quantity of pressure-sensitive explosive. When crushed, the explosive would detonate, sending a stream of hot gas down a hole in the nipple, and into the touchhole of the gun. In the process of firing, the cap generally split open, and would fall off, when the hammer was moved to half-cock position for loading. The caplock system worked well, and is still the preferred method of ignition for hunters and recreational shooters who use muzzle-loading arms. This article is becoming very long. ... The percussion cap or primer was the crucial invention that enabled firearms to fire in any weather. ... A gas is one of the four major phases of matter (after solid and liquid, and followed by plasma, that subsequently appear as a solid material is subjected to increasingly higher temperatures. ... Hunting is, in its most general sense, the pursuit of a target. ... A muzzle can be: The mouth of a firearm, see firearm muzzle The projecting nose of an animal, see animal muzzle An arrangement of straps used to bind an animal muzzle shut, or otherwise prevent it from biting. ...


Internal priming

Chemical primers, advanced metallurgy and manufacturing techniques all came together in the 1800s to create an entirely new class of firearm — the cartridge arm. Flintlock and caplock shooters had long carried their ammunition in paper cartridges, which served to hold a measured charge of powder, and a bullet in one convenient package (the paper also served to seal the bullet in the bore). Still, the source of ignition was separate. With the advent of chemical primers, it was not long before all sorts of systems were invented, with a multitude of different ways of combining bullet, powder, and primer into one package which could quickly be loaded from the breech of the firearm. The three systems which have survived the test of time are the rimfire, the Berdan primer, and the Boxer primer. Look up primer in Wiktionary, the free dictionary. ... Metallurgy is a domain of materials science and of materials engineering that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys. ... Manufacturing, a branch of industry which accounts for about one-quarter of the worlds economic activity, is the application of tools and a processing medium to the transformation of raw materials into finished goods for sale. ... Beginning of the Napoleonic Wars (1805 - 1815). ... Boxes of ammunition clog a warehouse in Baghdad Ammunition is a generic military term meaning (the assembly of) a projectile and its propellant. ... A blank sheet of paper Paper is a commodity of thin material produced by the amalgamation of fibers, typically vegetable fibers composed of cellulose, which are subsequently held together by hydrogen bonding. ... This article does not cite its references or sources. ... .357 Magnum cartridges, containing bullets A bullet is a solid projectile propelled by a firearm and is normally made from metal (usually lead). ... Look up breech in Wiktionary, the free dictionary. ...


Rimfire: Rimfire cartridges use a thin brass case with a bulge, or rim, around the back end. This rim is filled, during manufacture, with an impact-sensitive primer. In the wet state, the primer is stable; a pellet of wet primer is placed in the shell, and simply spun out to the full extremes of the rim. (For more on the exact process and one set of chemical compounds that have been used successfully, see U.S. Patent 1880235 , a 1932 Remington Arms patent by James E. Burns.) In the dry state, the primer within the rim becomes impact-sensitive. When the rim is then crushed by the hammer or firing pin, the primer detonates and ignites the powder charge. Rimfire cartridges are single-use — after firing, they cannot practically be reloaded. Also, since the rim must be thin enough to be easily crushed, the pressures generated in the case are limited by the strength of this thin rim. Rimfire cartridges were previously available in calibers up to .44, but all except the small .22 caliber rounds died out. The .22 Long Rifle (which is also fired in pistols) is the most popular recreational caliber, because it is inexpensive, quiet, and has very low recoil. The most inexpensive brands can be bought for less than US$0.02 per round in boxes of 500, and even Olympic class ammunition is around US$0.20 per round. Brass is any alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses, each of which has unique properties[1]. Note that in comparison bronze is principally an alloy of copper and tin. ... The word calibre (British English) or caliber (American English) designates the interior diameter of a tube or the exterior diameter of a wire or rod. ... .22 Long Rifle - Subsonic Hollowpoint (Left), Standard Velocity (Center), Hyper-Velocity Stinger Hollowpoint (Right). ... A Browning 9 millimeter Hi-Power Ordnance pistol of the French Navy, 19th century, using a Percussion cap mechanism Derringers were small and easily hidden. ... An early naval cannon design, allowing the gun to roll backwards a small distance when firing The recoil when firing a gun is the backward momentum of a gun, which is equal to the forward momentum of the bullet or shell, due to conservation of momentum. ... The five Olympic rings were designed in 1913, adopted in 1914 and debuted at the Games at Antwerp, 1920. ... Boxes of ammunition clog a warehouse in Baghdad Ammunition is a generic military term meaning (the assembly of) a projectile and its propellant. ...


While the rimfire priming method is limited due to the thin cases required, it has enjoyed a few resurgences in the recent past. First was Winchester's .22 Magnum Rimfire, or .22 WMR, in the 1950s, followed in 1970 Remington's short lived 5 mm Magnum Rimfire, based on Winchester's magnum case. In 2002 Hornady introduced a new .17 caliber cartridge based on the .22 WMR, the .17 HMR. The .17 HMR is essentially a .22 WMR cartridge necked down to accept a .17 caliber bullet, and is used as a flat-shooting, light duty varmint round. The .17 HMR was followed a year later by the Hornady's .17 Mach 2, or .17 HM2, which is based on a slightly lengthened and necked down .22 Long Rifle cartridge. Both of the .17 caliber rimfires have had widespread support from firearms makers, and while the high-tech, high velocity .17 caliber jacketed bullets make the .17 Rimfire cartridges quite a bit more expensive than the .22 caliber versions, they are still far less expensive than comparable centerfire cartridges. The . ... // Recovering from World War II and its aftermath, the economic miracle emerged in West Germany and Italy. ... 1970 (MCMLXX) was a common year starting on Thursday (the link is to a full 1970 calendar). ... For album titles with the same name, see 2002 (album). ... Hornady is a firearm ammunition manufacturer founded by Joyce Hornady. ... A . ... Vermin is a term given to animals which are considered by humans to be pests or nuisances, most associated with the carrying of disease. ... The . ... .17 Rimfire refers to a . ...


Berdan Primer: The remaining types of priming, Berdan and Boxer, are both considered "centerfire", to differentiate them from the rimfire rounds. Centerfire priming methods are interchangeable; the same firearm can fire both Berdan- and Boxer-primed rounds.


Berdan primers are named after their American inventor, Hiram Berdan of New York who invented his first variation of the Berdan primer and patented it on March 20, 1866, in U.S. Patent 53388 . A small copper cylinder formed the shell of the cartridge, and the primer cap was pressed into the outside end of the cartridge opposite the bullet from the outside. In the end of the cartridge beneath the primer cap was a single vent-hole, as well as a small "teat-like projection" or point fashioned from the case, later to be known as an anvil, upon which to provide a hard surface behind the primer cap such that the firing pin would have a hard surface against which to crush the primer and ignite the propellant. This system worked well, allowing the option of installing a cap just before use of the propellant-loaded cartridge, as well as permitting re-loading the cartridge for re-use. Difficulties arose in practice because pressing in the cap from the outside tended to cause a swelling of the copper cartridge shell, preventing the reliable seating of the cartridge in the chamber of the firearm. Berdan's solution was to change to brass shells, and to further modify the process of installing the primer cap into the cartridge, as noted in his second Berdan Primer patent of September 29, 1869, in U.S. Patent 82587 . Berdan primers have remained essentially the same functionally to the present day. Hiram Berdan Hiram Berdan (1823-1893) is an American engineer and military man, creator of United States Sharpshooters and inventor of Berdan rifle, Berdan Sharps rifle and numerous other weapons. ... March 20 is the 79th day of the year in the Gregorian Calendar (80th in leap years). ... 1866 (MDCCCLXVI) is a common year starting on Monday of the Gregorian calendar or a common year starting on Wednesday of the 12-day-slower Julian calendar. ... September 29 is the 272nd day of the year (273rd in leap years) in the Gregorian calendar. ... 1869 (MDCCCLXIX) is a common year starting on Friday (link will take you to calendar) of the Gregorian calendar or a common year starting on Sunday of the 12-day-slower Julian calendar. ...


Berdan primers are similar to the caps used in the caplock system — being small metal cups, with pressure-sensitive explosive in them. Modern-day Berdan primers are pressed into the primer "pocket" of a Berdan-type cartridge case, where they fit slightly below, flush with the base of the case. Inside the primer pocket is a small bump, the "anvil", that rests against the center of the cup, and two small holes that allow flash from the primer to reach the interior of the case. Berdan cases are reusable, although the process is rather involved. The used primer must be removed, usually by hydraulic pressure, or a lever that pulls the primer out of the bottom. A new primer is carefully seated against the anvil, and then gunpowder and a bullet are added. Berdan priming is used by nearly all militaries and most civilian manufacturers, with the exception of those in the USA. Hydraulics is a branch of science and engineering concerned with the use of liquids to perform mechanical tasks. ...


Boxer Primers: Meanwhile, Edward M. Boxer, of the Royal Arsenal in Woolwich, England was working on a similar primer cap design for cartridges, patenting it in England on October 13, 1866, and subsequently receiving a U.S. patent for his design on June 29, 1869, in U.S. Patent 91,818 . October 13 is the 286th day of the year (287th in leap years) in the Gregorian calendar. ... 1866 (MDCCCLXVI) is a common year starting on Monday of the Gregorian calendar or a common year starting on Wednesday of the 12-day-slower Julian calendar. ... June 29 is the 180th day of the year (181st in leap years) in the Gregorian Calendar, with 185 days remaining. ... 1869 (MDCCCLXIX) is a common year starting on Friday (link will take you to calendar) of the Gregorian calendar or a common year starting on Sunday of the 12-day-slower Julian calendar. ...


Boxer primers are similar to Berdan primers with one major change — the location of the anvil. In a Boxer primer, the anvil is a separate piece that sits in the primer cup. Because of this, the primer pocket has the flash-hole, centered. This makes little or no difference to the performance of the round, but it makes fired primers vastly easier to remove for re-loading. A thin metal rod is pushed through the mouth of the case, and it pushes the primer out. A new primer, anvil included, is then pressed into the case. Since the primer and anvil are sold as one part, the anvil depth must be correct for the primer that is being inserted, so that the primer does not ignite during loading (although priming is done as the first step, before the powder is added). This is the main reason why Boxer priming is still popular in the USA, as there are a large number of shooters who reload their ammunition.


Boxer-primed ammunition is slightly more complex to manufacture, since the primer is in two parts, but the slight increase in initial cost is often more than equalized by the decreased cost of firing reloaded rounds, at least for users intending to reload rounds. However, in much military-surplus ammunition, Berdan-primed ammunition is often found to be more common, having been both cheaper and faster to produce for filling very-large orders intended for military use. Military-surplus Berdan-primed ammunition is also often corrosive or slightly-corrosive, whereas Boxer-primed ammunition is often non-corrosive, although assuming corrosive or non-corrosive characteristics on the basis of whether Berdan or Boxer primed is never fool-proof.


Sizes Of Primers: Primers come in different sizes, based on the application. The types/sizes of primers are:

  • For both pistol and rifle: Small and Large, in Standard and Magnum versions.
  • .209 primers for shotgun shells and modern inline muzzleloaders.
  • .50 BMG primers, used for the .50 Browning Machine Gun cartridge and derivatives
  • Specialty primers for extremely small centerfire cases, or for large cannon cartridges

Examples of uses: The word Magnum, derived from the Latin word magnus (English: great), has been applied to several things: Some people named Magnum, or the Great: Alexander III of Macedon, Megas Alexandros Pompey, Gnaeus Pompeius Magnus Pope Gregory I, Gregorius Magnus Pope Leo I, Leo Magnus Charles king of Franks, Carolus Magnus... A shotgun shell is a self-contained cartridge loaded with shot or a slug designed to be fired from a shotgun. ... A US soldier drops a shell into the muzzle of an M224 60-mm mortar. ... A . ... A wildcat cartridge, or wildcat, is a custom cartridge for which ammunition and firearms are not mass produced. ... A small cannon on a carriage, Bucharest. ...

The primer size is based on the primer pocket of the cartridge, with standard types available in large or small diameters. The primer explosive charge is based on the amount of ignition required by the cartridge design; a standard primer would be use for smaller charges or faster burning powders, while a magnum primer would be used for larger charges or slower burning powders. The magnum primers increase the impulse power of powder, by supplying a hotter and stronger spark. The main differences between pistol and rifle primers are the amount of force required to ignite the primer and the amount of spark produced. The primary difference between pistol and rifle primers is the thickness of the primer's case; pistol primers are thinner, softer, and easier to ignite, while rifle primers are thicker, stronger, and require a harder hit from the firing pin. Despite the names pistol and rifle, the primer used depends on the cartridge, not the firearm; high pressure pistol cartridges like the .221 Fireball and .454 Casull use rifle primers, while low pressure cartridges like traditional revolver cartridges commonly used in lever action rifles would still be loaded with pistol primers. . ... .357 Magnum Colt Python revolver .357 Magnum ammunition. ... .45 ACP cartridges .45 redirects here. ... The . ... NATO 7. ... Winchester Short Magnum, or WSM, refers to a family of cartridges developed by the U.S. Repeating Arms Company, the maker of Winchester guns [1] and one of the oldest firearms manufacturers in the United States, in the early 2000s. ... The firing pin is a very hard steel rod with a one small, rounded end for striking the primer of a cartridge. ... The Remington XP-100 (from eXperimental Pistol number 100) is a bolt action pistol produced by Remington Arms from 1963 to 1998. ... The . ... rEVOLVEr (2004) is the fourth studio album release by Swedish thrash metal band The Haunted. ... A lever-action is a type of firearm which uses a lever located around the trigger guard area (often including the trigger guard itself) to load fresh cartridges into the chamber of the barrel when the lever is cranked. The most famous of such lever-action firearms are the Martini...


Electrical

A growing number of civilian arms are switching to electrical primers. Electrical primers use an electrical charge, powered by a battery, to detonate the primer. Such primers decrease the time between pulling the trigger and ignition of the charge. The control circuitry attendant with these primers also offers opportunities for biometric safety locks, remote trigger mountings, and tele-operation of the weapon.


Propellant

Black powder

Black powder is a mix of sulphur, charcoal, and potassium nitrate or sodium nitrate. Unlike smokeless propellants, it acts more like an explosive since its burn rate is not affected by pressure. However, it is a very poor explosive because it has a very slow decomposition rate, and therefore a very low brisance. Black powder was the original gunpowder and practically the only known propellant and explosive until the middle of the 19th century. ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Atomic mass 32. ... Charcoal is the blackish residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. ... R-phrases   S-phrases   Supplementary data page Structure and properties n, εr, etc. ... Made of Porn and sex things Inhalation respiratory irritation Skin May cause irritation. ... The use of water pressure - the Captain Cook Memorial Jet in Lake Burley Griffin, Canberra. ... Brisance is a measure of the rapidity with which an explosive develops its maximum pressure. ...


Nitrocellulose

Nitrocellulose is formed by the action of nitric acid on cellulose fibers. It is a highly combustible plastic that deflagrates rapidly, when heat is applied. It also burns very cleanly, burning almost entirely to gaseous components at high temperatures. The burning rate of nitrocellulose is dependent upon the pressure — a pile of uncontained nitrocellulose will burn slowly, with a high, bright flame, but when placed in a high strength, sealed container, the same material will burn very quickly, bursting the container. Since nitrocellulose is a plastic, it can be formed into many shapes of gunpowder, such as cylinders, tubes, balls, and flakes. The size and shape of the powder grains can increase or decrease the relative surface area, and change the burn rate significantly. Additives and coatings can be added to the powder to further modify the burn rate. Normally, very fast powders are used for low-velocity pistols and shotguns, medium-rate powders for magnum pistols and light rifle rounds, and slow powders for large-bore heavy rifle rounds.[1] Nitrocellulose Nitrocellulose Nitrocellulose (also: cellulose nitrate, flash paper) is a highly flammable compound formed by nitrating cellulose through, for example, exposure to nitric acid or another powerful nitrating agent. ... The chemical compound nitric acid (HNO3), also known as aqua fortis and spirit of nitre, is an aqueous solution of hydrogen nitrate (anhydrous nitric acid). ... Cellulose as polymer of β-D-glucose Cellulose in 3D Cellulose (C6H10O5)n is a long-chain polymeric polysaccharide carbohydrate, of beta-glucose [1][2]. It forms the primary structural component of green plants. ... This article or section does not adequately cite its references or sources. ... A log in a fire place. ... Fig. ... It has been suggested that this article or section be merged with Fire. ... This article or section does not adequately cite its references or sources. ... This article explains the meaning of area as a Physical quantity. ... A Browning 9 millimeter Hi-Power Ordnance pistol of the French Navy, 19th century, using a Percussion cap mechanism Derringers were small and easily hidden. ... A pump-action and two semi-automatic action Remington 1100 shotguns, 20 boxes of shotgun shells, a clay trap, and three boxes of clay pigeons. ... It has been suggested that Break action be merged into this article or section. ...


Double base propellants

To further increase the energy of smokeless powder, nitroglycerin can be added in amounts up to 50%. These powders are called "double base powders", and they have the same basic physical properties as single base powders. The nitrocellulose serves to desensitize the highly unstable nitroglycerin, and the nitroglycerin greatly increases the energy density of the resulting powder. Double base powders burn faster than single base powders of the same shape, and in general, the higher the nitroglycerin content of a powder, the faster the burn rate. Nitroglycerin (NG), also known as nitroglycerine, trinitroglycerin, and glyceryl trinitrate, is a chemical compound. ...


Solid propellants

A recent topic of research has been in the realm of "caseless cartridges". In a caseless cartridge, the propellant is cast as a single solid grain, with the priming compound placed in a hollow at the base, and the bullet glued to the front. Since the single propellant grain is so large (most smokeless powders have grain sizes around 1 mm, a caseless grain will be perhaps 7 mm diameter and 15 mm long), the relative burn rate must be much higher. To reach this rate of burning, caseless propellants often use moderated explosives, such as RDX. [edit] Headline text ANEWNGONEWGEQWMedia:Example. ...


While there is at least one experimental military rifle (the H&K G11), and one commercial rifle (made by Voere), that use caseless rounds, they are not having much success. The caseless ammunition is by necessity, not reloadable (a major disadvantage in civilian markets, where reloading is common), and the exposed propellant makes the rounds less rugged. Also, the case in a standard cartridge serves as a seal, keeping gas from escaping the breech. Caseless arms must use a more complex self-sealing breech, which increases the design and manufacturing complexity. Another problem, common to all auto-loading arms but particularly problematic for those firing caseless rounds, is the problem of rounds "cooking off". This is caused by residual heat from the chamber heating the round in the chamber to the point where it ignites, causing an unintentional discharge. Look up breech in Wiktionary, the free dictionary. ... Cooking off is when ammunition is set off prematurely due to heat in the surrounding environment. ...


Belt-fed machine guns, designed for high volumes of fire, are designed to fire from an open bolt, which means that the round is not chambered until the trigger is pulled, and so there is no chance for the round to cook off before the operator is ready. Open-bolt designs are generally undesirable for anything but belt-fed machineguns and pistol-sized sub-machine guns. The reason is that the mass of the bolt, moving forward, causes the gun to lurch in reaction, which significantly reduces the accuracy of the gun. Since one of the motivating factors for the use of caseless rounds is to increase the rate of fire to the degree that several shots can be fired to the same point of aim, anything that reduces the accuracy of those first shots would be counterproductive. Cased ammunition serves as a heat sink to both carry heat away from the chamber after firing, and to cool the chamber when chambered, reducing the risk of cook off.


Load density and consistency

Load density is the percentage of the space in the cartridge case that is filled with powder. In general, loads close to 100% density (or even loads where seating the bullet in the case, compresses the powder) ignite and burn more consistently than lower density loads. In cartridges that survived from the black powder cartridge era (examples being .45 Colt, .45-70 Government), the case is much larger than needed to hold the maximum charge of high-density smokeless powder. This allows the powder to shift in the case, piling up near the front, or near the back of the case. This can cause significant variations in burning rate, as powder near the rear of the case will ignite rapidly, but powder near the front of the case will ignite slower. This change has less impact with fast powders. As such, high-capacity, low-density cartridges generally deliver best accuracy with the fastest appropriate powder, although this keeps the total energy low, due to the sharp, high pressure peak. In physics, density is defined as mass m per unit volume V. Mathematically, it is expressed as where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is the volume of the substance... The percent sign A percentage is a way of expressing numbers as fractions of 100 and is often denoted using the percent sign, %. For example, 45. ...


Magnum pistol cartridges reverse this power/accuracy trade off, by using lower density powders that give high load density, and a broad pressure curve. The downside is the increased recoil and muzzle blast from the high powder mass, and high muzzle pressure. The advantage is that the magnum pistol rounds generate accuracy, comparable to a good hunting rifle, and energy sufficient to take medium game at ranges out to 100 yards (100 meters) and beyond.


Most rifle cartridges have a high load density with the appropriate powders. Rifle cartridges tend to be bottlenecked, with a wide base narrowing down to a smaller diameter, to hold a light, high-velocity bullet. These cases are designed to hold a large charge of low-density powder, for an even broader pressure curve than a magnum pistol cartridge. These cases require the use of a long rifle barrel to extract their full efficiency, although they are also chambered in rifle-like pistols (single shot or bolt action) with barrels of 10 to 15 inches (25 to 38 cm).


One unusual phenomenon occurs when high density powders are used in large capacity rifle cases. Small charges of powder, unless held tightly near the rear of the case by wadding, can apparently detonate when ignited. The mechanism of this phenomenon is not well-known, and generally it is not encountered, except when loading very low velocity subsonic rounds for rifles. These rounds generally have velocities of under 500 ft/s (195 m/s), and are used for indoor shooting, or pest control, where the power and muzzle blast of a full power round is not needed or desired. Wadding is used in guns to seal gas behind a projectile. ... A weapons cache is detonated at the East River Range on Bagram Airfield, Afghanistan Detonation is a process of supersonic combustion that involves a shock wave and a reaction zone behind it. ... Subsonic has two possible meanings: A speed lower than the speed of sound is called subsonic. ... Pest control refers to the regulation or management of another species defined as a pest, usually because it is detrimental to a persons health, the ecology or the economy. ...


This detonation problem seems strange because we intuitively think that less propellant will produce less power. A possible explanation for it lies with the relationship between the temperature, pressure and volume of a gas and the fact that the rate at which the propellant burns increases very rapidly with increase of temperature. Temperature is proportional to pressure/volume. So as pressure increases the temperature increases proportionally but as volume increases the temperature falls proportionally to the inverse of the volume. When a normal cartridge is fired under normal circumstances the bullet moving down the barrel increases the volume containing the hot high pressure gas. That reduces its temperature and holds down the burn rate which is the generator of pressure. This acts as a kind of control as the propellant keeps burning down two thirds or more of the barrel. With a low, non packed charge, the explosion of the primer swirls the propellant particles around in its hot gasses and ignites all of them simultaneously rather than progressively. Because the mass of propellant is so low, the same heat input from the primer heats them to a higher initial temperature and so their first stage burn is at a higher rate. Because there is only a small amount of propellant the pressure is not at first high enough to start the bullet moving quickly and so there is time for the propellant to burn completely at high temperature and pressure while it is still in a small space. It is easy to see that this could create the circumstances for detonation as the increase of volume fights to control the temperature and burn rate.


Chamber

Straight vs bottleneck

Straight walled cases were the standard from the beginnings of cartridge arms. With the low burning speed of black powder, the best efficiency was achieved with large, heavy bullets, so the bullet was the largest practical diameter. The large diameter allowed a short, stable bullet with high weight, and the maximum practical bore volume to extract the most energy possible in a given length barrel. There were a few cartridges that had long, shallow tapers, but these were generally an attempt to use an existing cartridge to fire a smaller bullet with a higher velocity and lower recoil. With the advent of smokeless powders, it was possible to generate far higher velocities by using a slow smokeless powder in a large volume case, pushing a small, light bullet. The .30-30 Winchester was one of the first rounds to be designed to use smokeless powder, and it has a distinct shoulder that closely resembles modern cartridges, even though it dates back to the 1890s. Modern cases have shorter necks, sharper shoulder angles, and a rimless design which give better efficiency and feeding, but the .30-30 cartridge and the Winchester model 1894 rifle still account for more game in North America than any other rifle and cartridge combination. DIAMETER is an AAA protocol (Authentication, Authorization and Accounting) succeeding its predecessor RADIUS. // The name is a pun on the RADIUS protocol, which is the predecessor (a diameter is twice the radius). ... The volume of a solid object is the three-dimensional concept of how much space it occupies, often quantified numerically. ... Smokeless powder Smokeless powder is the name given to a number of gunpowder-like propellants used in firearms which produce negligible smoke when fired, unlike the older black powder which it replaced. ... Winchester Model 1894 The Winchester rifle has become synonymous with the word repeating rifle (multishot rifle) which was manufactured by the Winchester Repeating Arms Company and was commonly used in the United States during the latter half of the 19th century. ... The 1890s were sometimes referred to as the Mauve Decade, because William Henry Perkins aniline dye allowed the widespread use of that colour in fashion, and also as the Gay Nineties, under the then-current usage of the word gay which referred simply to merriment and frivolity, with no... World map showing North America A satellite composite image of North America. ...


Aspect ratio and consistency

When selecting a rifle cartridge for maximum accuracy, a short, fat cartridge with very little case taper will generally yield higher efficiency and more consistent velocity than a long, thin cartridge with a lot of case taper (part of the reason for a bottle-necked design). Given current trends towards shorter and fatter cases, such as the new Winchester Super Short Magnum cartridges, it appears the ideal might be a case approaching spherical inside[2]. Target and varmint hunting rounds require the greatest accuracy, so their cases tend to be short, fat, and nearly untapered with sharp shoulders on the case. Short, fat cases also allow short-action weapons to be made lighter and stronger for the same level of performance. The trade-off for this performance is fat rounds which take up more space in a magazine, sharp shoulders that do not feed as easily out of a magazine, and less reliable extraction of the spent round. For these reasons, when reliable feeding is more important than accuracy, such as with military rifles, longer cases with shallower shoulder angles are favored. There has been a long-term trend however, even among military weapons, towards shorter, fatter cases. The current 7.62 x 51 mm NATO case replacing the longer .30-06 Springfield is a good example, as is the new 6.5 Grendel cartridge designed to increase the performance of the AR-15 family of rifles and carbines. Vermin is a term given to animals which are considered by humans to be pests or nuisances, most associated with the carrying of disease. ... This article or section does not adequately cite its references or sources. ... 6. ... The AR-15 is a lightweight, air-cooled, magazine-fed, autoloading, centerfire rifle. ...


Friction and inertia

Static friction and ignition

Since the burning rate of smokeless powder varies directly with the pressure, the initial pressure buildup has a significant effect on the final velocity, especially in cartridges with fast powders. The friction, holding the bullet in the case, determines how soon after ignition the bullet moves, and since the motion of the bullet increases the volume and drops the pressure, a difference in friction can change the slope of the pressure curve. In general, a tight fit is desired, to the extent of crimping the bullet into the case. In straight-walled rimless cases, such as the .45 ACP, an aggressive crimp is not possible, since the case is held in the chamber by the mouth of the case, but sizing the case to allow a tight interference fit with the bullet, can give the desired result. The velocity of an object is its speed in a particular direction. ... Friction is the force that opposes the relative motion or tendency toward such motion of two surfaces in contact. ... This article or section is in need of attention from an expert on the subject. ... Crimp or crimping can mean: Crimp (gambling) Crimp (wool) Crimp (joining) Crimp (recruitment) Crimp (climbing) Grain crimping Hair crimping Crimping Pliers This is a disambiguation page — a list of articles associated with the same title. ... An Interference fit is a fastening between two components which is achieved by friction after the parts are pushed together, rather than by any other means of fastening. ...


Kinetic friction

The bullet must tightly fit the bore to seal the high pressure of the burning gun powder. This tight fit generates a large quantity of friction. The friction of the bullet in the bore does have a slight impact on the final velocity, but that is generally not much of a concern. Of greater concern is the heat that is generated, due to the friction. At velocities of about 1000 ft/s (390 m/s), lead begins to melt, and deposit in the bore. This lead build-up constricts the bore, increasing the pressure and decreasing the accuracy of subsequent rounds, and is difficult to scrub out, without damaging the bore. Rounds, used at velocities up to 1500 ft/s (585 m/s), can use wax lubricants on the bullet to reduce lead build-up. At velocities over 1500 ft/s (585 m/s), nearly all bullets are jacketed in copper, or a similar alloy that is soft enough not to wear on the barrel, but melts at a high enough temperature to reduce build-up in the bore. Copper build-up does begin to occur in rounds that exceed 2500 ft/s (975 m/s), and a common solution is to impregnate the surface of the bullet with molybdenum disulfide lubricant. This reduces copper build-up in the bore, and results in better long-term accuracy. For PB or pb as an abbreviation, see PB. General Name, Symbol, Number lead, Pb, 82 Chemical series poor metals Group, Period, Block 14, 6, p Appearance bluish gray Atomic mass 207. ... Bore may refer to: A wave in a river caused by an incoming tide - see tidal bore The diameter of a pipe or tube, or the caliber of a gun The diameter of a cylinder and piston in a piston engine (See also: Stroke) A person who is boring The... candle wax This page is about the substance. ... A lubricant (colloquially, lube, although this may also refer to personal lubricants) is a substance (usually a liquid) introduced between two moving surfaces to reduce the friction and wear between them. ... General Name, Symbol, Number copper, Cu, 29 Chemical series transition metals Group, Period, Block 11, 4, d Appearance metallic pinkish red Atomic mass 63. ... An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ... Molybdenum disulfide, also called molybdenum sulfide or molybdenum(IV) sulfide, with the formula MoS2, is a black crystalline sulfide of molybdenum. ... A lubricant (colloquially, lube, although this may also refer to personal lubricants) is a substance (usually a liquid) introduced between two moving surfaces to reduce the friction and wear between them. ...


The role of inertia

In the first few inches (centimeters) of travel down the bore, the bullet reaches a significant percentage of its final velocity, even for high-capacity rifles, with slow burning powder. The acceleration is on the order of tens of thousands of gravities, so even a projectile as light as 40 grains (2.6 g), can provide hundreds of pounds-force (over 1000 newtons) of resistance, due to inertia. Changes in bullet mass, therefore, have a huge impact on the pressure curves of smokeless powder cartridges, unlike black powder cartridges. This makes loading or reloading smokeless cartridges require high-precision equipment, and carefully-measured tables of load data for given cartridges, powders, and bullet weights. Acceleration is the time rate of change of velocity, and at any point on a velocity-time graph, it is given by the slope of the tangent to that point In physics or physical science, acceleration (symbol: a) is defined as the rate of change (or derivative with respect to... Gravity is a force of attraction that acts between bodies that have mass. ... The pound-force is a non-SI unit of force or weight (properly abbreviated lbf or lbf). The pound-force is equal to a mass of one pound multiplied by the standard acceleration due to gravity on Earth (which is defined as exactly 9. ... The newton (symbol: N) is the SI unit of force. ... The principle of inertia is one of the fundamental laws of classical physics which are used to describe the motion of matter and how it is affected by applied forces. ...


Pressure

This is a graph of a simulation of the 5.56 mm NATO round, being fired from a 20-inch barrel. The horizontal axis represents time, the vertical axis represents pressure (green line), bullet travel (red line), and bullet velocity (light blue line). The values shown at top are peak values
This is a graph of a simulation of the 5.56 mm NATO round, being fired from a 20-inch barrel. The horizontal axis represents time, the vertical axis represents pressure (green line), bullet travel (red line), and bullet velocity (light blue line). The values shown at top are peak values

Energy is imparted to the bullet in a firearm by the pressure of the gases produced by the burning gunpowder. While it seems to casual observers that a higher peak pressures should produce higher velocities, that is not always the case, since measures of peak pressure capture only a small fraction of the time the bullet is accelerating. To achieve maximum performance, the entire duration of the bullet's travel through the barrel must be considered. Internal ballistics plot of simulated 5. ... Internal ballistics plot of simulated 5. ... Wooden mechanical horse simulator during WWI. A simulation is an imitation of some real thing, state of affairs, or process. ... NATO 2002 Summit in Prague The North Atlantic Treaty Organisation[2] (NATO; French: ; also called the North Atlantic Alliance, the Atlantic Alliance, or the Western Alliance) is a military alliance established by the signing of the North Atlantic Treaty on 4 April 1949. ... A coordinate axis is one of a set of vectors that defines a coordinate system. ...


There are hundreds of powders in existence because powders must be carefully matched to the case volume, case dimensions, bullet dimensions, bullet weight, barrel length, and special bullet features such as moly coating or driving bands. For example, long, heavy bullets are required to be seated so deep in the case that they displace powder, while at the same time requiring a slower powder which gives their greater mass more time to move down the barrel. If the bullet is banded or coated with a lubricant like moly, faster powders can be used as the bullet moves faster due to decreased friction with the barrel. All of these variables must be accommodated within the maximum pressure levels set for the platform. Finding the optimum combination is largely a trial and error process, and may take years to complete. New cartridges with significantly new internal ballistics often bring forth new powders engineered to maximize performance; examples of this are Accurate Arms 2230, designed for use in the .223 Remington, and #9, designed for use in magnum pistol cartridges[1][2]. The . ...


Pressure vs distance traveled

 This graph shows different pressure curves for powders with different burn rates. The leftmost graph is the same as the large graph above. The middle graph shows a powder with a 25% faster burn rate, and the rightmost graph shows a powder with a 20% slower burn rate.
This graph shows different pressure curves for powders with different burn rates. The leftmost graph is the same as the large graph above. The middle graph shows a powder with a 25% faster burn rate, and the rightmost graph shows a powder with a 20% slower burn rate.

Using powder that is too fast creates a destructive pressure spike that usually has a very short duration. Using powder that is too slow produces poor energy and leaves a lot of unburned powder. Internal ballistics plot showing effects of medium, faster, and slower burning powders This is a screenshot of copyrighted computer software. ... Internal ballistics plot showing effects of medium, faster, and slower burning powders This is a screenshot of copyrighted computer software. ...


Peak vs area

Energy is defined as a force exerted over a distance; for example, the work required to lift a one-pound weight, one foot against the pull of gravity defines a foot-pound of energy (lifting one newton, one meter gives one newton-meter of energy, called one joule). If we were to modify the graph to reflect pressure as a function of distance, the area under that curve would be the total energy imparted to the bullet. From this, it can be seen that the way to increase the energy of the bullet is to increase the area under that curve, either by raising the average pressure, or increasing the distance, the bullet travels under pressure (in other words, lengthen the barrel). In physics, force is an influence that may cause a body to accelerate. ... Distance is a numerical description of how far apart things lie. ... The newton (symbol: N) is the SI unit of force. ... The metre, or meter (symbol: m) is the SI base unit of length. ... The joule (IPA pronunciation: or ) (symbol: J) is the SI unit of energy. ...


Propellant burnout

Another issue to consider, when choosing a powder burn rate, is the time the powder takes to completely burn vs. the time the bullet spends in the barrel. Since the burn rate of nitrocellulose-based powders increases with increasing pressure, this can be a very difficult interaction to guess, and requires careful testing with gradual changes. Looking carefully at the left graph, there is a change in the curve, at about 0.8 ms. This is the point at which the powder is completely burned, and no new gas is created. With a faster powder, burnout occurs earlier, and with the slower powder, it occurs later. Propellant that is unburned when the bullet reaches the muzzle is wasted — it adds no energy to the bullet, but it does add to the recoil and muzzle blast. For maximum power, the powder should burn until just short of the muzzle. Look up Burnout in Wiktionary, the free dictionary. ...


Since smokeless powders burn, not detonate, the reaction can only take place on the surface of the powder. Smokeless powders come in a variety of shapes, which serve to determine how fast they burn, and also how the burn rate changes as the powder burns. The simplest shape is a ball powder, which is in the form of round or slightly flattened spheres. Ball powder has a fairly small surface-area-to-volume ratio, so it burns fairly slowly, and as it burns, its surface-area-to-volume ratio decreases. This means as the powder burns, the burn rate slows down.


To some degree, this can be negated by the use of retardant coatings on the surface of the powder, which slows the initial burn rate further, and flattens out the rate of change. Ball powders are generally formulated as slow pistol powders, or fast rifle powders. Flake powders are in the form of flat, round flakes which have a very high surface-area-to-volume ratio. Flake powders have a nearly constant rate of burn, and are usually formulated as fast pistol or shotgun powders. The last common shape is an extruded powder, which is in the form of a cylinder, sometimes hollow. Extruded powders generally have a lower ratio of nitroglycerin to nitrocellulose, and are often progressive burning — that is, they burn at a faster rate as they burn. Extruded powders are generally medium to slow rifle powders. A pump-action and two semi-automatic action Remington 1100 shotguns, 20 boxes of shotgun shells, a clay trap, and three boxes of clay pigeons. ...


Muzzle pressure concerns

From the pressure graphs, it can be seen that the residual pressure in the barrel, as the bullet exits, is quite high — in this case, over 16 kpsi / 110000 kPa. / 1100 bar. While lengthening the barrel, or reducing the amount of propellant gas, will reduce this pressure, this is often not possible due to issues of firearm size, and minimum required energy. Short-range target guns are, generally, chambered in .22 Long Rifle, or .22 Short, which have very tiny powder capacities, and little residual pressure. When higher energies are required for long-range shooting, hunting or anti-personnel use, high muzzle pressures are a necessary evil. With this high muzzle pressures come increased flash and noise from the muzzle blast, and due to the large powder charges used, higher recoil — recoil includes the reaction for, not just the bullet, but also for the powder mass. In general, a residual is a positive or negative numeric difference between two numbers. ...


General concerns

Bore diameter and energy transfer

A firearm, in many ways, is like a piston engine on the power stroke. There is a certain amount of high-pressure gas available, and energy is extracted from it, by making the gas move a piston — in this case, the projectile is the piston. The swept volume of the piston determines how much energy can be extracted from the given gas. The more volume that is swept by the piston, the lower is the exhaust pressure (in this case, the muzzle pressure). Any remaining pressure is lost energy. Components of a typical, four stroke cycle, DOHC piston engine. ... The word exhaust can mean:- A verb meaning tire out, as in After the long gallop, his horse was exhausted. ...


To extract the maximum amount of energy, then, the swept volume is maximized. This can be done in one of two ways — increasing the length of the barrel, or increasing the diameter of the projectile. Increasing the barrel length will linearly increase the swept volume, while increasing the diameter will increase the swept volume as the square of the diameter. Since barrel length is limited by practical concerns to about arm's length for a rifle, and much shorter for a handgun, increasing bore diameter is the normal way to increase the efficiency of a cartridge. The limit to bore diameter is generally the sectional density of the projectile (see external ballistics). Larger diameter bullets have much more drag, and so they lose energy very quickly after exiting the barrel. In general, most handguns use bullets between .355 (9 mm) and .45 (11.5 mm) caliber, while most rifles generally range from .223 (5.56 mm) to .32 (8 mm) caliber. There are many exceptions, of course, but bullets in the given ranges provide the best general purpose performance. Handguns use the larger diameter bullets for greater efficiency in short barrels, and tolerate the long-range velocity loss, since handguns are seldom used for long-range shooting. Handguns that are used for long-range shooting are generally closer to shortened rifles than other handguns. External ballistics is the part of ballistics tht refers to the behavior of a bullet after it exits the barrel and before it hits the target. ... An object falling through a gas or liquid experiences a force in direction opposite to its motion. ... A handgun is a firearm small enough to be carried and used in one hand. ...


Ratio of propellant to projectile mass

Another issue, when choosing or developing a cartridge, is the issue of recoil. The recoil is not just the reaction from the projectile being launched, but also from the powder gas, which will exit the barrel with a velocity, even higher than that of the bullet. For handgun cartridges, with large bullets and small powder charges (a 9 mm, for example, might use 5 grains (320 mg) of powder, and a 115 grain (7.5 g) bullet), this is not a significant force; for a rifle cartridge (a .22-250 Remington, using 40 grains (2.6 g) of powder and a 40 grain (2.6 g) bullet), the powder charge can make for the majority of the recoil force. This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...


There is a solution to the recoil issue, though it is not without cost. A muzzle brake or recoil compensator is a device which redirects the powder gas at the muzzle, usually up and back. This acts like a rocket, pushing the muzzle down and forward. The forward push helps negate the feel of the projectile recoil by pulling the firearm forwards. The downward push, on the other hand, helps counteract the rotation imparted by the fact that most firearms have the barrel mounted above the center of gravity. Overt combat guns, large-bore high-powered rifles, long-range handguns chambered for rifle ammunition, and action-shooting handguns designed for accurate rapid fire, all benefit from muzzle brakes. Compensator can refer to: A muzzle brake, used to counter the recoil of a firearm, or to prevent the muzzle from climbing during rapid fire A device that offsets or counterbalances a destabilising factor: See Buoyancy compensator, Static VAr compensator, Heisenberg compensator, Lead-lag compensator A pressure control on a... This article or section may contain original research or unverified claims. ... Wiktionary:Open - definition Open set (mathematics) Open (sport) - A type of competition in tennis and golf (among others) where entry is open to all qualifiers regardless of age. ... Combate Naval de Iquique - oil on canvas painting by Thomas Somerscales, XIX century Combat, or fighting, is purposeful violent conflict between one or more persons or organizations, often intended to establish dominance over the opposition. ... Look up chamber in Wiktionary, the free dictionary. ...


The high-powered firearms use the muzzle brake mainly for recoil reduction, which reduces the battering of the shooter by the severe recoil. The action-shooting handguns redirect all the energy up to counteract the rotation of the recoil, and make following shots faster by leaving the gun on target. The disadvantage of the muzzle brake is a longer, heavier barrel, and a large increase in sound levels behind the muzzle of the rifle. Shooting firearms without hearing protection can eventually damage the operator's hearing. Shooting firearms with muzzle brakes, with no hearing protection, can damage it far faster. Even with adequate hearing protection, the increased pounding of the redirected muzzle blast can quickly cause headaches. Batter can have several meanings: In cooking, batter is a thick or thin mixture, usually made of a ground grain, a liquid, and a fat. ...


Powder-to-projectile-weight ratio also touches on the subject of efficiency. In the case of the .22-250 Remington, more energy goes into propelling the powder gas than goes into propelling the bullet. The .22-250 pays for this by requiring a large case, with lots of powder, all for a fairly small gain in velocity and energy over other .22 caliber cartridges.


Accuracy and bore characteristics

Nearly all small bore firearms, with the exception of shotguns, have rifled barrels. The rifling imparts a spin on the bullet, which keeps it from tumbling in flight. The rifling is usually in the form of sharp edged grooves cut as helixes along the axis of the bore, anywhere from 2 to 16 in number. The areas between the grooves are known as lands. A helix (pl: helices), from the Greek word έλικας/έλιξ, is a twisted shape like a spring, screw or a spiral (correctly termed helical) staircase. ...


Another system, polygonal rifling, gives the bore a polygonal cross section. Polygonal rifling is not very common, used by only a few European manufacturers. The companies that use polygonal rifling claim greater accuracy, lower friction, and less lead and/or copper buildup in the barrel. Traditional land and groove rifling is used in most competition firearms, however, so the advantages of polygonal rifling are unproven. Look up polygon in Wiktionary, the free dictionary. ... This article is 150 kilobytes or more in size. ...


There are three common ways of rifling a barrel:

  • The most basic is to use a single point cutter, drawn down the bore by a machine that carefully controls the rotation of the cutting head relative to the barrel. This is the slowest process, but as it requires the simplest equipment, it is often used by custom gunsmiths, and can result in superbly accurate barrels.
  • The next method is button rifling. This method uses a die with a negative image of the rifling cut on it. This die is drawn down the barrel while carefully rotated, and it swages the inside of the barrel. This "cuts" all the grooves at once (it does not really cut metal), and so is faster than cut rifling. Detractors claim that the process leaves considerable residual stress in the barrel, but world records have been set with button-rifled barrels, so again there is no clear advantage.
  • The last method used is hammer forging. In this process, a slightly undersized, bored barrel is placed around a mandrel that contains a negative image of the entire length of the rifled barrel. The barrel and mandrel are rotated and hammered by power hammers, which forms the inside of the barrel all at once. This is the fastest (and in the long run, cheapest) method of making a barrel, but the equipment is prohibitively expensive for all, but the largest, gun makers. Hammer-forged barrels are strictly mass-produced, so they are generally not capable of top accuracy as produced, but with some careful hand work, they can be made to shoot far better than most shooters are capable of.

The purpose of the barrel is to provide a consistent seal, allowing the bullet to accelerate to a consistent velocity. It must also impart the right spin, and release the bullet consistently, perfectly concentric to the bore. The residual pressure in the bore must be released symmetrically, so that no side of the bullet receives any more or less push than the rest. The muzzle of the barrel is the most critical part, since that is the part that controls the release of the bullet. Some rimfires and airguns actually have a slight constriction, called a choke, in the barrel at the muzzle. This guarantees that the bullet is held securely just before release. A gunsmith is a person who designs, builds, repairs or modifies firearms to blueprint and customer specifications, using hand tools and machine tools such as grinders and lathes. ... Look up die in Wiktionary, the free dictionary. ... A blacksmiths forge For finery forges (making iron) see finery forge. ... Mandrel (pronounced mandrul, and also transliterated as manderil) is a term that can refer to: an object used to shape machined work; a tool component that grips or clamps materials to be machined; or a tool component that can be used to grip other moving tool components. ... Compression seal example A mechanical seal is a device which helps join systems or mechanisms together by preventing leakage (e. ... Concentric objects share the same center, axis or origin with one inside the other. ... Symmetry is a characteristic of geometrical shapes, equations and other objects; we say that such an object is symmetric with respect to a given operation if this operation, when applied to the object, does not appear to change it. ... Air guns are weapons that propel a bullet using compressed air or another gas, possibly liquefied. ... Constriction is a method used by various snake species to kill their prey. ... Look up Choke in Wiktionary, the free dictionary. ...


To keep a good seal, the bore must be a very precise, constant diameter, or have a slight decrease in diameter from breech to muzzle. Any increase in bore diameter will allow the bullet to shift. This can cause gas to leak past the bullet, affecting the velocity, or cause the bullet to tip, so that it is no longer perfectly coaxial with the bore. High quality barrels are lapped to remove any constrictions in the bore which will cause a change in diameter. coaxial cable In geometry, coaxial means that two or more forms share a common axis; it is the three-dimensional analog of concentric. Coaxial cable, for example, has a conducting wire in the center and a second conducting layer running all the way around the exterior circumference, under the insulation. ...


The lapping process uses a lead "slug" that is slightly larger than the bore and covered in fine abrasive compound to cut out the constrictions. The slug is passed from breech to muzzle, so that as it encounters constrictions, it cuts them away, and does no cutting on areas that are larger than the constriction. Many passes are made, and as the bore becomes more uniform, finer grades of abrasive compound are used. The final result is a barrel that is mirror-smooth, and with a consistent or slightly-tapering bore. The hand-lapping technique uses a wooden or soft metal rod to pull or push the slug through the bore, while the newer fire-lapping technique uses specially-loaded, low-power cartridges to push abrasive-covered soft-lead bullets down the barrel. An abrasive is a material that is used to smooth, machine, or, in some cases, roughen another softer material through extensive rubbing. ... A chemical compound is a chemical substance consisting of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. ...


Another issue that has an effect on the barrel's hold on the bullet is the rifling. When the bullet is fired, it is forced into the rifling, which cuts or "engraves" the surface of the bullet. If the rifling is a constant twist, then the rifling rides in the grooves engraved in the bullet, and everything is secure and sealed. If the rifling has a decreasing twist, then the changing angle of the rifling in the engraved grooves of the bullet causes the rifling to become narrower than the grooves. This allows gas to blow by, and loosens the hold of the bullet on the barrel. An increasing twist, however, will make the rifling become wider than the grooves in the bullet, maintaining the seal. When a rifled-barrel blank is selected for a gun, careful measurement of the inevitable variations in manufacture can determine if the rifling twist varies, and put the higher-twist end at the muzzle. Engraving is the practice of incising a design onto a hard, flat surface, by cutting grooves into it. ... There are a number of uses for the word blank: For reverting page blanking, see Wikipedia:Vandalism. ...


The muzzle of the barrel is the last thing to touch the bullet before it goes into ballistic flight, and as such has the greatest potential to disrupt the bullet's flight. The muzzle must allow the gas to escape the barrel symmetrically; any asymmetry will cause an uneven pressure on the base of the bullet, which will disrupt its flight. The muzzle end of the barrel is called the "crown", and it is usually either beveled or recessed to protect it from bumps or scratches that might affect accuracy. A sign of a good crown will be a symmetric, star-shaped pattern on the muzzle end of the barrel, formed by soot deposited, as the powder gases escape the barrel. If the star is uneven, then it is a sign of an uneven crown, and an inaccurate barrel. Symmetry is a characteristic of geometrical shapes, equations and other objects; we say that such an object is symmetric with respect to a given operation if this operation, when applied to the object, does not appear to change it. ... A bevel is a slant or angle on a surface. ... Soot, also called lampblack, Pigment Black 7, carbon black or black carbon, is a dark powdery deposit of unburned fuel residues, usually composed mainly of amorphous carbon, that accumulates in chimneys, automobile mufflers and other surfaces exposed to smoke—especially from the combustion of carbon-rich organic fuels in the...


Before the barrel can release the bullet in a consistent manner, it must grip the bullet in a consistent manner. The part of the barrel between where the bullet exits the cartridge, and engages the rifling, is called the "throat", and the length of the throat is the "freebore". In some firearms, the freebore is all but nonexistent — the act of chambering the cartridge forces the bullet into the rifling. This is common in low-powered rimfire target rifles. The placement of the bullet in the rifling ensures that the transition between cartridge, and rifling, is quick and stable. The downside is that the cartridge is firmly held in place, and attempting to extract the unfired round can be difficult, to the point of even pulling the bullet from the cartridge in extreme cases.


With high-powered cartridges, there is an additional disadvantage to a short freebore. A significant amount of force is required to engrave the bullet, and this additional resistance can raise the pressure in the chamber by quite a bit. To mitigate this effect, higher-powered rifles tend to have more freebore, so that the bullet is allowed to gain some momentum, and the chamber pressure is allowed to drop slightly, before the bullet engages the rifling. The downside is that the bullet hits the rifling when already moving, and any slight misalignment can cause the bullet to tip, as it engages the rifling. This will, in turn, mean that the bullet does not exit the barrel coaxially. The amount of freebore is a function of both the barrel and the cartridge. The manufacturer or gunsmith who cuts the chamber will determine the amount of space between the cartridge case mouth and the rifling. Setting the bullet further forward or back in the cartridge can decrease or increase the amount of freebore, but only within a small range. Careful testing by the ammunition loader can optimize the amount of freebore to maximize accuracy, while keeping the peak pressure within limits.


Autoloading firearms

Autoloading firearms (this term covers automatic and semi-automatic firearms) harness some of the energy of firing to load a new round from an ammunition-feeding device. This loading generally involves:

  • extracting and ejecting the fired cartridge case;
  • obtaining a new cartridge from a clip, magazine or belt, cocking the hammer or striker; and
  • securing the new cartridge in the chamber, ready to fire.

Automatic firearms will, if the trigger remains depressed, also fire the new round, upon finishing the cycle. There are a number of different mechanisms to harness the energy required, and they vary in complexity and suitability for different purposes.


One issue that applies to all autoloading mechanisms is the mass of the reciprocating components. In all cases, the firing energy is harnessed to open the mechanism, and a spring or springs are used to close the mechanism. The spring must have sufficient energy to close the action, and perform all tasks that are involved in that, but the spring itself does very little to keep the action closed. The energy that powers the action is only available for the time it takes for the projectile to leave the barrel, or less. This energy is converted to kinetic energy in the reciprocating parts, and the amount of energy required to propel those parts to the required velocity, is what is needed for reliable operation with a given powder, bullet, and cartridge combination. Since changing the mass of the firearm parts is out of the scope of the average user (this amounts to a redesign of the firearm in most cases), it is up to the user to select ammunition that will allow the firearm to function. The kinetic energy of an object is the extra energy which it possesses due to its motion. ...


Blowback firearms

The simplest autoloading firearms are known as "blowback actions". In a blowback gun, the bolt that holds the cartridge in the chamber is held in place by a spring, called the recoil spring. Upon firing, the same pressure that pushes the bullet forward, pushes the case backwards. The same effect that operates the Blish lock operates between the cartridge and the chamber walls, which serves to hold the case in the breech for a small amount of time. This effect is not enough to keep it there, however, and the case pushes out of the chamber, moving the bolt with it. The bolt is far more massive than the bullet, so the bolt moves only a very short distance, before the bullet exits the barrel, and the pressure drops to ambient. In this short distance, however, the bolt has gained sufficient momentum to eject the cartridge, cock the hammer, and compress the recoil spring. The compressed recoil spring then forces the bolt back forward, chambering a new round. One interesting advantage of the blowback action is the fact that an extractor, used to pull the cartridge out of the chamber, is not required during firing, since the cartridge is pushing the bolt out. Since extractors tend to be one of the more delicate parts of most firearms designs, this helps increase reliability under extreme conditions. The Blish Lock is a friction-lock designed by John Bell Blish, that takes advantage of the fact that under extreme pressures, certain dissimilar materials will resist movement through friction greater than normal friction laws would predict. ... Ambient music is a loosely defined musical genre that incorporates elements of a number of different styles - including jazz, electronic music, new age, rock and roll, modern classical music, reggae, traditional, world and even noise. ...


Blowback actions are very simple, and inexpensive to build. They are also generally very reliable. Most semi-automatic rimfires, and many submachine guns, are blowback actions. The disadvantage of the blowback action is the requirement that the bolt be so much heavier than the bullet. This is why its use is generally restricted to handguns in calibers of 9 mm Parabellum or smaller, and in carbines and submachine guns to calibers of .45 ACP and smaller. for the French rock group see Parabellum (band) The term parabellum comes from the Latin for prepare for war. The term is often heard in relation to ammunition – for example, nine millimeter parabellum. Parabellum ammunition is designed to be legal under international law; usually this means that rounds are full... A carbine is a firearm, similar to but shorter than an ordinary rifle or musket in barrel and stock. ...


There are a number of actions that are, in essence, blowback designs, but use a variety of approaches to reduce the velocity of the bolt, so that a combination of heavier bullets and lighter bolts may be used. These are called "delayed blowback actions". Techniques involve using:

  • a separate Blish lock mechanism;
  • a piston that fills with powder gas to push the bolt closed; and
  • a two-part cammed-bolt that uses the first bit of the cartridges movement to move the main body of the bolt back a large distance. See roller-delayed blowback.

These designs allow slightly higher-powered cartridges to be used with no additional modifications. The cammed-bolt design has been used with high-powered rifle cartridges with some success. However, it also requires the addition of a fluted chamber to reduce the Blish-lock effect, which would otherwise blow the back out of the cartridge. James Blish (East Orange, New Jersey, May 23, 1921 - Henley-on-Thames, July 29, 1975) was an American author of fantasy and science fiction. ... Roller-delayed blowback is a firearm operating principle, a refined form of blowback. ...


Gas-operated firearms

Gas-operated firearms differ from blowback actions in that the bolt is solidly locked into the breech of the barrel, at the time of firing. This locking can be done with a rotating cam, or a lateral bolt, or any number of other ways. In this, gas-operated firearms are not significantly different than manually operated bolt, pump, or lever-action designs. What makes a difference is how energy is provided to unlock, and open the bolt. At some point in the barrel, there is a small hole called a "gas tap", which allows the high-pressure gas to escape. This hole can be anywhere from just in front of the chamber to just behind the muzzle. This gas is directed into a cylinder and piston arrangement (fixed cylinder and moving piston, or fixed piston and moving cylinder, both have been used). The movement of the piston or cylinder is captured to provide the energy to operate the action. monkey ...


The concerns, when making ammunition for gas operated firearms, center around the gas tap location and the operating parameters of the cylinder and piston. The pressure in the barrel, as the bullet passes the gas tap, must be within a certain range of pressure, and the pressure must persist for a certain amount of time. Too little, and there will not be enough inertia gathered, to cycle the action; too much, and parts will move too fast to operate reliably, and the extra inertia will greatly increase wear and tear. The formulation of the powder must also be considered. Some powders produce more soot than others, and this soot can build up in the gas tap, or piston and cylinder area, and cause malfunctions. The gas tap is also subject to fouling from lead-buildup in guns that can fire non-jacketed bullets.


A case in point is the original M-16 rifle, which is a gas operated firearm. It was designed to use an IMR-type powder, which had certain burn characteristics. The U.S. military, against the advice of the designer, switched to a ball-type powder, with a different burn rate which yielded higher velocities. This also altered the pressure at the gas tap enough to increase the bolt velocity enough to tear apart cartridges, cause misfeeds, and generally turn what was a reliable rifle into a nightmare situation. M16 is also the Eagle Nebula in astronomy. ...


Gas action firearms require fairly high pressures to operate, and so are generally found in high-powered hunting or military rifles, and magnum pistols.


Recoil-operated firearms

The last common type of autoloading firearm is the recoil-operated type. Recoil-operated firearms, as the name implies, rely on the recoil generated by firing, rather than the gas pressure, used by blowbacks and gas-operated firearms. Recoil-operated firearms are locked-breech firearms, and come in three varieties, long recoil, short recoil, and inertia operation.


Long recoil operation is fairly rare, and used in heavily recoiling firearms, like shotguns, automatic grenade launchers, and heavy machine guns. In a long recoil action, the barrel and bolt recoil as a unit, separate from the rest of the gun, compressing two recoil springs on the way. When the bolt and barrel reach the full rearward extent, the bolt locks back, and the barrel springs forward, propelled by one of the recoil springs. When the barrel reaches the full forward position, then the bolt is released, and moves forward under the power of the other recoil spring. A grenade launcher is weapon that fires or launches a grenade to longer distances than a soldier could throw by hand. ...


Short recoil operation is almost exclusively found in pistols, and it is the most common action type in pistols of 9 mm Parabellum or greater. In a short recoil action, the barrel and bolt travel backwards for only a short distance before the barrel is unlocked (usually by a camming action), and the bolt continues on its own. When the bolt returns to the barrel, still locked in the rearward position, the barrel is cammed back into the locked position, and the gun is again ready to fire. Two notable exceptions are the excellent MG-42/MG3 machine gun and Barrett .50 caliber sniper rifle [3]


Inertia operation is a fairly new design, and is currently used almost exclusively in shotguns. Rather than the bolt and barrel recoiling independently of the frame of the firearm, inertia action uses the recoil of the entire gun relative to the bolt carrier. This recoil compresses a spring between the bolt and carrier, and when the carrier rebounds under the spring pressure, the resulting movement cycles the action. This requires a heavy recoil, which is why it is chosen for shotguns. A pump-action and two semi-automatic action Remington 1100 shotguns, 20 boxes of shotgun shells, a clay trap, and three boxes of clay pigeons. ...


Ammunition intended for recoil-operated guns needs to generate a sufficient amount of recoil to move the bolt and barrel back at the required velocity. This means that bullet weights are the primary concern. Cutting the bullet mass in half would require doubling the velocity to compensate, which would be doubling the kinetic energy compared to the heavy bullet. This requires a much heavier load of faster burning powder and a much higher peak pressure, which is usually not possible given the pressure constraints of the cartridge. Because of this it is rare to find a short recoil gun that can handle a minimum bullet mass that is less than half the maximum mass, and most have a much smaller range of weights.


References

  1. ^ Powder Burnrate Chart
  2. ^ http://www.cabelas.com/story-123/boddington_short_mag/10201/The+Short+Mag+Revolution.shtml The Short Mag Revolution
  3. ^ Barrett semi-automatic .50 caliber short-action sniper rifle

See also


  Results from FactBites:
 
Ballistics For Dummies (2420 words)
Internal ballistics has to do with what happens inside the rifle from the moment of ignition to the bullet's exiting the muzzle.
Ballistic Coefficient is a different matter entirely; it's the measure of how "streamlined" a bullet is, i.e., its effectiveness at overcoming air resistance during flight.
Because with so many folks out there owning ballistics programs for their personal computers, all you need to do is plug in muzzle velocity, bullet weight and BC and you can plot trajectories for any desired zero range.
What Is Ballistics? (1113 words)
Interior ballistics covers the events inside a gun that occur from the time the firing pin strikes the primer until the bullet exits the muzzle.
While the internal ballistics of large cartridges such as cannons are reliably predictable from mathematical considerations, interior ballistics for small arms are difficult to predict at least by reasonable calculation procedures.
Ballistics for "point blank range" calculations are based on a series of correlations developed and published by Dr. Ralph McGehee in the early 70's.
  More results at FactBites »

 
 

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