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Background

A bullet is a projectile, often a pointed metal cylinder, that is shot from a firearm. The bullet is usually part of an ammunition cartridge, the object that contains the bullet and that is inserted into the firearm. Cartridges are often called bullets, but this article will discuss only the projectiles fired from small or personal firearms (such as pistols, rifles, and shotguns).

History

Though there were cast lead bullets used with slings thousands of years ago, the history of the modern bullet starts with the history of firearms. Sometime after A.D. 1249, it was realized that gunpowder could be used to fire projectiles out of the open end of a tube. The earliest firearms were large cannons, but personal firearms appeared in the mid-fourteenth century. Early projectiles were stone or metal objects that could fit down the barrel of the firearm, though lead and lead alloys (mixtures of metals) were the preferred materials by 1550. As manufacturing techniques improved, firearms and lead bullets became more uniform in size and were produced in distinct calibers (the diameter of the bullet).

The Industrial Revolution produced further improvements. Firearms with rifled barrels (spiral grooves inside of the firearm barrel that impart stabilizing spinning motion to the bullet) led to the familiar conical bullet. More powerful smokeless powders replaced gunpowder (now called black powder) in the late nineteenth century, but they also required harsher firearm and bullet materials. Lead bullets left lead residue in the barrel; jacketed bullets (a harder metal layer surrounds the softer lead core) were developed to stop this. The familiar metal ammunition cartridge (containing a bullet, a case, a primer, and a volume of propellant) was common by World War I.

Raw Materials

Bullets are made of a variety of materials. Lead or a lead alloy (typically containing antimony) is the traditional bullet core material. Traditional bullet jackets are made of copper or gilding metal, an alloy of copper and zinc. There are many other materials that are used in bullets today, including aluminum, bismuth, bronze, copper, plastics, rubber, steel, tin, and tungsten.

Bullet lubricants include waxes (traditionally carnauba wax made from the carnauba palm), oils, and molybdenum disulfide (moly). Modern wax and oil formulas are generally not made public. Moly is a recent innovation; this naturally occurring mineral sticks to metal on contact. The bullet making process can also use grease and oils to lubricate the bullet during machining and pressing steps. This lubrication prevents damage to the bullet or the machinery by allowing the bullet and machinery to move against each other without sticking. Solvents are used to remove grease and oil from the bullet afterward.

Design

There are several different uses for ammunition, such as military, law enforcement, hunting, marksmanship/target shooting, and self-defense, each requiring different bullet performance. There are also legal and public relations design considerations, such as lethality, threats to innocent bystanders, environmental impact, and appearance.

Bullet design is dependent on firearm design and vice versa. The bullet must fit into the barrel correctly. A bullet that is too small will not engage the rifling in the barrel, or it will bounce around in the barrel and not exit in a straight line. A bullet that is too large will jam in the barrel, possibly causing the firearm to explode from the pressure. The bullet weight must also match the amount of powder in the cartridge, so that it is fired at the correct speed.

Bullets are designed using calculations and data gathered from previous testing (firing) of bullets. This data can include variables such as accuracy (whether it hit the target), precision (whether more than one of the same bullet type produced similar results), speed of the bullet, effectiveness at a given range (distance to the target), penetration into the target, and damage to the target. Bullets are then tested against a target which resembles what they will be used against. There are several materials used to simulate the intended target, including bullet gelatin, a recently developed material used to simulate flesh.

Modern bullets can have many different features. Some of these features concern the shape of the bullet and others the materials of construction. Most bullets look like a cylinder with a pointed end. The cylindrical section to the rear of the bullet is the shank and the pointed section to the front of the bullet is the tip, though the tip may be flat instead of pointed. Bullets can be made of one or more materials.

Bullets made out of only soft material (such as lead) expand on impact causing more damage to the target. Bullets made out of only a harder material (such as steel) penetrate further into thicker targets, but do not expand much. A softer core can be enclosed or partially enclosed in a layer of harder metal called a jacket. This jacket can completely enclose the bullet or it can leave the softer tip exposed for expansion purposes. Varying the amount of jacketing alters the amount of penetration versus expansion.

The shank can have a flat base or a tapered base (boat tail). The flat base is heavier and provides greater penetration, but the boat tail provides greater accuracy over distance. The base of the shank can also have a base plate of harder metal to prevent deformation of the bullet during firing. The base sometimes has a conical indentation (a gas check) that expands on firing to seal the base of the bullet against the firearm barrel and trap all of the energy from firing to propel the bullet forward. The shank may also have grooves used to contain lubricating grease that helps the bullet move freely in the firearm barrel. Sometimes a single groove, called a cannelure, is cut into the bullet to mark how far the bullet is to be inserted into the cartridge and to provide a feature to crimp the cartridge to the bullet.

The tip of the bullet is usually pointed. This point may be curved (called an ogive). Sharper tips provide greater penetration. Wadcutters are bullets with no point or a sharp shoulder behind the point used in target shooting to cut paper targets cleanly. Semiwadcutter bullets have a flat-tipped cone tip and can be used for target shooting, hunting, or self-defense. Target bullets are light and designed for speed and accuracy in a shooting range. They are usually not appropriate for other purposes.

Some tips are designed to expand on impact. This kind of bullet is banned from military use, but can be used for law enforcement, self-defense, and hunting. The tip or the entire bullet may be made of a soft material such as lead, but there are other design features that can aid bullet expansion. Hard material behind the softer tip provides more penetration and pushes the softer tip forward to expand more. The harder material can be the shank, a section of the tip, a partition of hard metal between the tip and the shank, or even a hard point on the tip that is driven backward on impact to expand the softer tip material.

Another feature that provides expansion is a hollow tip (or hollow point), an empty cone in the tip that points toward the rear of the bullet. When the bullet hits the target, the thin sides of the hollow tip expand outward. Even harder metals can expand, especially if they are scored (have grooves cut in them) to provide places to split apart.

Few bullets have separable parts. Some bullets have sabots, sleeves that surround the bullet while it is being fired but that fall off after leaving the firearm. Sabots allow smaller bullets to be fired from larger firearms at higher velocities than they would be fired from smaller firearms. Bullets can also contain multiple pellets or other particles that exit the bullet in a spray on impact or on leaving the target. This provides a higher chance of hitting something (from the many particles) or can cause many wounds in an easily damaged target.

Shotguns often fire shot (many small round pellets) or solid slugs (large, often soft bullets) out of an unrifled barrel, though some shotguns have rifled barrels. Air guns fire solid round or hourglass-shaped pellets.

Military bullets have special features, sometimes also used in law enforcement and self-defense. In order to get around the prohibition on expanding bullets, military bullets can be designed with heavier than normal back ends so that they tumble into the target on impact to create a larger wound. They can also be designed to break apart on impact with a similar effect. Some military bullets have incendiary (flammable) material in the base of the bullet that leaves a visible trail. This is known as a tracer bullet because it allows the shooter to track the bullet. Incendiary material can also be placed in the tip of the bullet so that it can start a fire on impact. Military bullets are usually made of harder materials or are fully jacketed. They are often designed for penetration. "Non-lethal" plastic or rubber bullets are sometimes used by the military and in law enforcement. These bullets are designed to temporarily incapacitate rioters and demonstrators, but they have the ability to kill.

Law enforcement and self-defense bullets should incapacitate the target. Many of these bullets are designed to expand or shatter after hitting the target, causing maximum damage. These bullets can be made of harder material that has greater penetration through materials such as heavy clothing and body armor. Police and self-defense bullets should not over penetrate (go through the target) and endanger bystanders.

Hunters have different requirements for different types of targets. Fast moving targets require faster, often lighter, bullets. Larger targets with heavy hides and large bones require bullets that can penetrate and inflict enough damage to drop the animal quickly. There are several different designs that address these conflicting demands. Many hunting bullets are designed to expand. Partitioned bullets and partially jacketed bullets are common for larger targets.

The Manufacturing
Process

There are many types of bullet manufacturers, ranging from large companies and governments to smaller custom ammunition manufacturers to individuals who load and reload ammunition with a few simple tools. There are also many different bullet designs and a lack of consensus about which is most effective. Because of this, there is no uniform method of ammunition manufacture. Large ammunition manufacturers, including the United States government, automate some of the manufacturing steps. At appropriate points during the manufacturing process, special features may be added.

The solid bullet or bullet core

The two most common bullet-forming methods are casting and swaging. Hollow points can be formed by either method. Hard (harder than lead) solid bullets can be stamped (a metal punch cuts a bullet-shaped piece out of a bar or sheet of softer metal) and machined from metal stock. Machining includes any process where a machine is used to shape metal by cutting away portions. A typical machine used for bullets is a lathe. A lathe rotates the bullet metal against steel chisels to gradually cut away material.

CASTING A BULLET

1. Casting is pouring molten metal into a mold. This mold is hinged and when closed has a hollow space that is the shape of the bullet. The metal is melted in a crucible (a metal or ceramic pot that can hold molten metal safely) and then poured into the mold.
2. After the metal has cooled, the mold is opened and the bullet falls or is knocked out. Any imperfections are removed by cutting or filing. If the bullet is extremely deformed, it can be melted down and the process repeated.
3. To cast a bullet with multiple sections of different materials, the first material is poured into the mold to partially fill it. After this material has cooled and partially or completely solidified, the second molten material is poured into the mold to fill it partially or completely. This can be done several times, but most often is done twice to create a bullet with a heavier section (for penetration) behind a softer section (for expansion).

SWAGING A BULLET

• Swaging is a cold forming process, which means that it involves shaping metal without heating to soften or melt it. The appropriate amount of material to be swaged (measured in grains) is placed in a die. A die is a harder metal container with a cavity (an empty space) shaped like the bullet without the back end. The die is part of a larger stationary object or is held in place on a platform.
• A metal punch that fits into the open end of the die is forced into the die to the appropriate depth. As the punch forces the bullet metal into the die cavity, the material takes the shape of the cavity. The pressure can come from a manual or hydraulic press, from repeated hammer blows, or from a threaded punch that is screwed on. Excess metal is squeezed out of bleed holes.
• The punch is removed from the die and the bullet is pushed or pulled out of the cavity. Any imperfections are removed by cutting or filing.
• Multiple swaging steps can be used to insert partitions, to create a bullet out of multiple materials, and to further define the shape of the bullet. Sometimes several steps are necessary to add features such as a hollow point.

The bullet jacket

Some bullets have jackets of harder metal surrounding a softer core.

• A coin-shaped piece of jacket metal is punched out of a strip or a sheet. The punch is usually a round metal cylinder that is pushed through the jacket material into a depression in a table. Some punches are rounded so that the piece of metal is shaped like a cup. Sometimes, tubing is used instead of a coin or a cup of metal.
• If the jacket material is too hard to be formed easily, it can be annealed. Annealing is heating the metal, often with a gas flame, to soften it and make it more workable.
• The jacket material is then placed in a die or over a punch and the punch is forced into the die. There may be several different punches and dies used to form specific features in the jacket. One of usual steps is to make sure that jacket is of uniform thickness. The thickness is typically 0.03-0.07 in (0.08-0.17 cm). Some bullets have a thin jacket electroplated onto the core.

Bullet assembly

• Jackets and multiple bullet parts can be joined by methods such as swaging them together, casting one section on top of another, soldering, gluing, or electrical welding. Soldering is a process of joining two pieces of metal together with solder, an alloy that is usually tin and lead. The solder is melted and sticks to both pieces of metal, gluing them together after it cools and solidifies. Glues for joining multi-part bullets are usually epoxies, plastics that are formed from two different fluids that harden when combined. The epoxy fluids are dispensed from tubes and mixed, then the pieces are joined together and held in place until the epoxy hardens. Electrical welding is the process of passing a strong electrical current through two metal parts that are in contact so that they soften and stick together. If the joining method is not strong enough, the bullet may fall apart prematurely.
• Next, grooves may be cut or pressed into the shank of the bullet. The grooves can be pressed into a soft bullet by rotating the bullet against a ridge on a metal wheel, or they can be cut into the bullet on a lathe. Many cast bullets already have grooves.
• The bullet is sometimes coated with a I O lubricant, usually wax, oil, or moly, which reduces bore fouling from soft bullets. Jacketed and hard bullets are not generally lubricated, though they can be, especially with moly. Bullets are often degreased (put in a solvent bath to remove grease from previous manufacturing steps) before the lubricant is applied.
• Wax and oil lubricants can be applied by rubbing with a soft material such as a cloth wheel, spraying, pouring, or dipping. Moly is applied by placing bullets in a container of moly powder and rotating the container so that the bullet and the moly particles tumble around until the bullet is coated.
• The completed bullets are then manually removed and packaged.

Quality Control

Many firearm users want consistent performance from their ammunition. The larger ammunition manufacturers responded by instituting quality control programs in the 1980s and 1990s. These programs include statistical process control (SPC), total quality management (TQM), and random testing. SPC involves measuring a manufacturing process and determining statistically how to optimize it so that it produces correct and consistent results. TQM is the application of this kind of quality control to the whole business, not just the manufacturing part of the business.

Random testing involves periodically taking a manufactured part and testing it. Completed bullets are loaded into ammunition and fired to determine if they perform as expected. Unfinished bullets can be examined to determine if they are being produced correctly up to that point in the manufacturing process. Both finished and unfinished bullets can be weighed, measured for symmetry (bullets should be identical along every direction from an imaginary line drawn from the center of the tip to the center of the base), and cut apart to make sure that there are no air spaces and that internal features are correct (such as the thickness of a partition or a jacket). Commercial bullet sizes can vary by thousandths of an inch, but military and high quality bullets are more uniform.

Byproducts/Waste

Up to 24 toxic materials have been found in ammunition production. Solvents (often used to remove oil and grease) are dangerous to inhale and can be captured for disposal or purification and reuse, as can any oil. Scrap metal can be reused or disposed.

The most dangerous raw material is lead. Production workers and firearm users can be exposed to dangerous levels of lead from bullets, and firing ranges, including military ones, are being shut down because of high lead levels. Lead can also leach into groundwater, further contaminating the environment. High levels of lead can lead to government intervention in the clean-up process, needing years of work to reach acceptable levels.

The Future

Companies continue to improve bullet performance to attract buyers, but social and political considerations are becoming more important. Health, safety, and environmental issues are leading to the replacement of toxic materials such as lead with materials such as tungsten, steel, bismuth, and plastic. Newer materials do not have the same performance characteristics as older materials, and this leads to newer ammunition designs.

There has been a legal struggle for decades over the lethality of police and self-defense weapons. Public outcry in the United States has been greatest against so-called "cop-killer" bullets designed to penetrate body armor such as that used by police, and against expanding bullets such as the Black Talon, which has a tip that opens into six sharp "claws" on impact.

Other innovations may be more radical. For example, tanks can fire shells with fins that pop out for stabilization at velocities that are too high for barrel rifling. This innovation could be scaled down for personal firearms. Self-propelled, finned rockets can also be shot out of pistol-sized launchers, though this type of projectile may no longer be called a bullet.

Where to Learn More

Books

Barnes, Frank C. Cartridges of the World. 9th ed. Ed. M. L. McPherson. lola, WI: Krause Publications, 2000.

Grennell, Dean A. The ABC s of Reloading. 5th ed. Northbrook, IL: DBI Books, Inc., 1993.

Periodicals

"Brass Hats Led To Tungsten." The Economist 352, no. 8130 (31 July 1999): 68.

Petzal, David E. "Rifles: 2000 and After." Field & Stream 103, no. 5 (September 1998): 87.

Stolinksky, David C. "Stopping Power: Myth or Science?"Handguns 14, no. 4 (April 2000): 38.

Zutz, Don. "The Story Behind Winchester's Supreme Effort." Shooting Industry 34, no. 12 (December 1989): 90.

Other

Gunnery Network Web Page. December 2001. <http://www.gunnery.net>.

Hasenauer, Heike. "Bushels of Bullets." Soldiers Magazine Online. November 1998. December 2001. <http://www.dtic.mil/soldiers/nov1998/features/ioc3.html>.

[Article by: Andrew Dawson]

In print production, a heavy mark, sometimes in the shape of a bullet (but more often a boldface dot), that is used to indicate an item of special interest or some special features on a page of copy.

The word ‘bullet’ can be applied to any projectile fired from a firearm. The earliest bullets were made of any hard material. Early in the history of firearms lead was found to be the ideal substance for bullets and remained so until the late 19th century. Lead was readily available, cheap, with a low melting point for easy moulding and of a high density for maximum effect. In some countries, Mexico for example, a lack of domestic lead supply led to the use of copper for much the same reasons.

Until the end of the 18th century, bullets were spherical and available in differing sizes for differing calibres of weapon. They were notoriously inaccurate, chiefly as a result of ‘windage’, or the loose fit they had in the barrels of smooth-bore military weapons. This loose fit was necessitated by the accretion of burnt gunpowder in the barrel after firing several rounds but was tolerated in order that a rapid rate of, albeit inaccurate, fire might be maintained. Riflemen used tightly fitting balls, forced into their rifled barrels with grease or lubricated patches of cloth, and gained resultant accuracy while sacrificing speed of loading. Various methods were investigated in the early 19th century to make musket balls fit tighter and thus be more accurate; most involved hammering the ball down the barrel, and against a projection at the breech end, in order to expand it to fit the barrel. All attempts were defeated by the burnt powder problem, together with the resultant lead residue left, and the development of conical bullets during the same period made little difference.

After many French experiments with conical bullets which expanded when hammered against pillars fixed in the breech, the solution was found in the cylindro-conoidal rifle bullet patented by Capt Claud-Etienne Minié in 1849. The bullet named after him had an iron cup in its base which forced the lead skirts into the rifling of a barrel; it had grooves around its base to accept grease for lubricated loading. Having solved the windage problem, the next goal was the attainment of increased accuracy. This was achieved following lengthy competition between Joseph Whitworth and William Metford, whose experiments in both bullet design and rifling occupied much of the 1860s. Metford's winning bullet, three times as long as it was in diameter, bridged the period between the old short, fat bullet and that which would—when fixed in a cartridge—take ammunition into the 20th century.

Lead bullets left extensive lead fouling in barrels when fired with high-velocity smokeless propellants and experiments with the jacketing of bullets occupied the 1890s. While most bullets have been jacketed with copper-zinc alloy, a variety of other hard metals, including tungsten, have been used. Modern warfare has necessitated differing types of bullet, for anti-armour, for tracing the fall of shot and for setting fire to combustible targets. Rubber and plastic bullets are used for riot control by security services and police worldwide.

Bibliography

• Blair, Claude (gen. ed.), Pollard's History of Firearms (London, 1983).
• Peterson, Harold L. (ed.), Encyclopaedia of Firearms (London, 1964).
• Roads, Dr Christopher H., The British Soldier's Firearm 1850-1864 (London, 1964)

— Stephen Wood

1) A one-time lump-sum repayment of an outstanding loan, typically made by the borrower after very little, if any, amortization of the loan. This can also refer to a loan that requires a disproportionately large portion (or even all) of the loan to be repaid at maturity.

2) A slang term for a letter of rejection sent to a job applicant, informing the candidate that he or she has not been offered the job, has been denied an interview or some similar form of rejection.

Investopedia Says:
1) Loans can have provisions built into them upon issuance to allow borrowers to make a one-time lump-sum repayment of the loan at their discretion. This option can prove useful for borrowers, particularly if their financial situation significantly changes for the better shortly after the loan is issued. For example, an early lump-sum repayment can considerably lower the interest expense accrued over the course of the loan.

2) Companies typically send out bullet letters once they have filled the position they had available, or (if the bullet letter denies an interview) once the company has selected its entire interview pool. In other cases, a company may simply state in the job advertisement that it will only contact applicants who are selected for an interview.

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Can be a symbol of violence, or of an attack. In traditional psychoanalysis, a bullet can be a sexual symbol (penis; impregnation). We also sometimes talk about "biting the bullet" and "sweating bullets."

1. projectile for a humane killer that uses a conventional or free bullet.
2. a metallic, bullet-shaped mass given orally so as to lodge in the reticulum and discharge its critical component over a long period. Bullets containing cobalt selenium or magnesium are in use. Called also reticular retention bullets.

• magnesium reticular b. — heavy pellets delivering about 1 g magnesium daily administered orally to cattle as a prevention against hypomagnesemia; the ‘bullets’ lodge in the reticulum and are retained there until they dissolve completely.

• Firearm Parts, Accessories, and Processes - bullet: small projectile discharged from firearm at great speed
• Card Terms
• Punctuation and Diacritics - bullet: • large, solid, vertically centered dot placed in printed matter to call attention to particular passage, or used for syllable divisions in dictionaries
• Drug Names and Forms - bullet: Slang. line or snort of cocaine

This article is about firearms projectiles. For other uses, see Bullet (disambiguation).

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (August 2009)

Lead soft-point, boat-tailed, copper-jacketed bullets

A bullet is a projectile propelled by a firearm, sling, or air gun. Bullets do not normally contain explosives,^[1] but damage the intended target by impact and penetration. The word "bullet" is sometimes repeatedly used to refer to ammunition in general, or to a cartridge, which is a combination of the bullet, case/shell, powder, and primer.

Contents 1 History 1.1 Pointed bullets 1.2 The modern bullet 2 Design 3 Propulsion 4 Materials 5 Treaties and prohibitions 6 Bullet abbreviations 7 Figurative uses 8 See also 9 References 10 External links

History

Lead sling bullets with a winged thunderbolt engraved on one side and the inscription "Take that" on the other side. 4th century BC. From Athens.

Matchlock musket balls, alleged to have been discovered at Naseby battlefield. From the collection of Night of the Museum and Art Gallery.

The history of bullets far predates the history of firearms. Originally, bullets were metallic or stone balls used in a sling as a weapon and for hunting. Eventually as firearms were developed, these same items were placed in front of an explosive charge of gun powder at the end of a closed tube. As firearms became more technologically advanced, from 1500 to 1800, bullets changed very little. They remained simple round (spherical) lead balls, called rounds, differing only in their diameter.

The development of the hand culverin and matchlock arquebus brought about the use of cast lead balls as projectiles. "Bullet" is derived from the French word boulette which roughly means little ball. The original musket bullet was a spherical lead ball smaller than the bore, wrapped in a loosely-fitted paper patch which served to hold the bullet in the barrel firmly upon the powder. (Bullets that were not firmly upon the powder upon firing risked causing the barrel to explode, with the condition known as a short start.) The loading of muskets was, therefore, easy with the old smooth-bore Brown Bess and similar military muskets. The original muzzle-loading rifle, on the other hand, with a more closely fitting ball to take the rifling grooves, was more difficult to load, particularly when the bore of the barrel was fouled from previous firings. For this reason, early rifles were not generally used for military purposes.

The first half of the nineteenth century saw a distinct change in the shape and function of the bullet. In 1826, Delvigne, a French infantry officer, invented a breech with abrupt shoulders on which a spherical bullet was rammed down until it caught the rifling grooves. Delvigne's method, however, deformed the bullet and was inaccurate.

Square bullets, invented by James Puckle and Kyle Tunis, were briefly used in one version of the Puckle gun. The use of these was soon discontinued due to irregular and unpredictable flight patterns.

Pointed bullets

Among the first pointed or "conical" bullets were those designed by Captain John Norton of the British Army in 1823. Norton's bullet had a hollow base which upon firing expanded under pressure to engage with a barrel's rifling. The British Board of Ordnance rejected it because spherical bullets had been in use for the previous 300 years.^{[citation needed]}

Renowned English gunsmith William Greener invented the Greener bullet in 1836. It was very similar to Norton's bullet except that the hollow base of the bullet was fitted with a wooden plug which more reliably forced the base of the bullet to expand and catch the rifling. Tests proved that Greener's bullet was extremely effective but it too was rejected for military use because, being two parts, it was judged as being too complicated to produce.

Minié ball ammunition

The soft lead Minié ball was first introduced in 1847 by Claude-Étienne Minié, a captain in the French Army. It was nearly identical to the Greener bullet. As designed by Minié, the bullet was conical in shape with a hollow cavity in the rear, which was fitted with a little iron cap instead of a wooden plug. When fired, the iron cap would force itself into the hollow cavity at the rear of the bullet, thereby expanding the sides of the bullet to grip and engage the rifling. In 1855, the British adopted the Minié ball for their Enfield rifles.

The small ball first saw widespread use in the American Civil War. Roughly 90% of the battlefield casualties in this war were caused by Minié balls fired from rifles.

Between 1854 and 1857, Sir Joseph Whitworth conducted a long series of rifle experiments, and proved, among other points, the advantages of a smaller bore and, in particular, of an elongated bullet. The Whitworth bullet was made to fit the grooves of the rifle mechanically. The Whitworth rifle was never adopted by the government, although it was used extensively for match purposes and target practice between 1857 and 1866, when it was gradually superseded by Metford's.

About 1862 and later, W. E. Metford carried out an exhaustive series of experiments on bullets and rifling, and invented the important system of light rifling with increasing spiral, and a hardened bullet. The combined result was that in December 1888 the Lee-Metford small-bore (0.303", 7.70 mm) rifle, Mark I, (photo of cartridge on right) was finally adopted for the British army. The Lee-Metford was the predecessor of the Lee-Enfield.

The modern bullet

.270 ammunition. Left to right:
100-grain (6.5 g) – hollow point
115-grain (7.5 g) – FMJBT
130-grain (8.4 g) – soft point
150-grain (9.7 g) – round nose

.303 inch (7.7 mm) centrefire, FMJ rimmed ammunition

The next important change in the history of the rifle bullet occurred in 1882, when Major Eduard Rubin, director of the Swiss Army Laboratory at Thun, invented the copper jacketed bullet — an elongated bullet with a lead core in a copper jacket. It was also small bore (7.5mm and 8mm) and it is the precursor of the 8mm "Lebel bullet" which was adopted for the smokeless powder ammunition of the Mle 1886 Lebel rifle.

The surface of lead bullets fired at high velocity may melt due to hot gases behind and friction with the bore. Because copper has a higher melting point, and greater specific heat capacity and hardness, copper jacketed bullets allow greater muzzle velocities.

European advances in aerodynamics led to the pointed spitzer bullet. By the beginning of the twentieth century, most world armies had begun to transition to spitzer bullets. These bullets flew for greater distances more accurately and carried more energy with them. Spitzer bullets combined with machine guns greatly increased the lethality of the battlefield.

The latest advancement in bullet shape was the boat tail, a streamlined base for spitzer bullets. The vacuum created as air moves at high speed passes over the end of a bullet slows the projectile. The streamlined boat tail design reduces this form drag by allowing the air to flow along the surface of the tapering end. The resulting aerodynamic advantage is currently seen as the optimum shape for rifle technology. The first combination spitzer and boat-tail bullet, named Balle "D" from its inventor (a lieutenant-colonel Desaleux), was introduced as standard military ammunition in 1901, for the French Lebel Model 1886 rifle .

Design

A modern cartridge consists of the following:
1. the bullet, which serves as the projectile;
2. the case, which holds all parts together;
3. the propellant, for example gunpowder or cordite;
4. part of the casing used for loading;
5. the primer, which ignites the propellant.

Bullet designs have to solve two primary problems. They must first form a seal with the gun's bore. If a strong seal is not achieved, gas from the propellant charge leaks past the bullet, reducing efficiency. The bullet must also engage the rifling without damaging the gun's bore. Bullets must have a surface which will form this seal without causing excessive friction. These interactions between bullet and bore are termed internal ballistics. Bullets must be produced to a high standard, as surface imperfections can affect firing accuracy.

The physics affecting the bullet once it leaves the barrel, is termed external ballistics. The primary factors affecting the aerodynamics of a bullet in flight are the bullet's shape and the rotation imparted by the rifling of the gun barrel. Rotational forces stabilize the bullet gyroscopically as well as aerodynamically. Any asymmetry in the bullet is largely canceled as it spins. With smooth-bore firearms, a spherical shape was optimum because no matter how it was oriented, it presented a uniform front. These unstable bullets tumbled erratically and provided only moderate accuracy, however the aerodynamic shape changed little for centuries. Generally, bullet shapes are a compromise between aerodynamics, interior ballistic necessities, and terminal ballistics requirements. Another method of stabilization is for the center of mass of the bullet to be as far forward as is practical, which is how the Minié ball and the shuttlecock are designed. This allows the bullet to fly front-forward by means of aerodynamics.

See Terminal ballistics and/or Stopping power for an overview of how bullet design affects what happens when a bullet impacts with an object. The outcome of the impact is determined by the composition and density of the target material, the angle of incidence, and the velocity and physical characteristics of the bullet itself. Bullets are generally designed to penetrate, deform, and/or break apart. For a given material and bullet, the strike velocity is the primary factor determining which outcome is achieved.

Bullet shapes are many and varied, and an array of them can be found in any reloading manual that sells bullet moulds. Mould manufacturers such as RCBS,^[2] Paul Jones Moulds, and David Mos offer many different calibers and designs. With a mould, bullets can be made at home for reloading one's own ammunition, where local laws allow. Hand-casting, however, is only time- and cost-effective for solid lead bullets. Cast and jacketed bullets are also commercially available from numerous manufacturers for hand loading and are much more convenient than casting bullets from bulk lead.

Propulsion

Propulsion of the ball can happen via several methods:

• by using only gunpowder (i.e. as in flintlock weapons)
• by using a percussion cap and gunpowder (i.e. as in percussion weapons)
• by using a cartridge (which contains primer, gunpowder and ball in a single package)

Materials

Expanding bullet loaded in a 6.5x55mm before and after expanding. The long base and small expanded diameter show that this is a bullet designed for deep penetration on large game. The bullet in the photo traveled more than halfway through a moose before coming to rest, performing as designed.

Bullets for black powder, or muzzle loading firearms, were classically molded from pure lead. This worked well for low speed bullets, fired at velocities of less than 450 m/s (1475 ft/s). For slightly higher speed bullets fired in modern firearms, a harder alloy of lead and tin or typesetter's lead (used to mold Linotype) works very well. For even higher speed bullet use, jacketed coated lead bullets are used. The common element in all of these, lead, is widely used because it is very dense, thereby providing a high amount of mass—and thus, kinetic energy—for a given volume. Lead is also cheap, easy to obtain, easy to work, and melts at a low temperature, which results in comparatively easy fabrication of bullets.

• Lead: Simple cast, extruded, swaged, or otherwise fabricated lead slugs are the simplest form of bullets. At speeds of greater than 300 m/s (1000 ft/s) (common in most handguns), lead is deposited in rifled bores at an ever-increasing rate. Alloying the lead with a small percentage of tin and/or antimony serves to reduce this effect, but grows less effective as velocities are increased. A cup made of harder metal, such as copper, placed at the base of the bullet and called a gas check, is often used to decrease lead deposits by protecting the rear of the bullet against melting when fired at higher pressures, but this too does not solve the problem at higher velocities.
• Jacketed lead: Bullets intended for even higher-velocity applications generally have a lead core that is jacketed or plated with gilding metal, cupronickel, copper alloys, or steel; a thin layer of harder metal protects the softer lead core when the bullet is passing through the barrel and during flight, which allows delivering the bullet intact to the target. There, the heavy lead core delivers its kinetic energy to the target. Full metal jacket or ball bullets (cartridges with ball bullets are called ball ammunition) are completely encased in the harder metal jacket, except for the base. Some bullet jackets do not extend to the front of the bullet, to aid expansion and increase lethality; these are called soft point or hollow point bullets. Steel bullets are often plated with copper or other metals for corrosion resistance during long periods of storage. Synthetic jacket materials such as nylon and Teflon have been used, with limited success.
• Blanks: Wax, paper, plastic, and other materials are used to simulate live gunfire and are intended only to hold the powder in a blank cartridge and to produce noise. The "bullet" may be captured in a purpose-designed device or it may be allowed to expend what little energy it has in the air. Some blank cartridges are crimped or closed at the end and do not contain any bullet.
• Practice: Made from lightweight materials like rubber, Wax, wood, plastic, or lightweight metal, practice bullets are intended for short-range target work, only. Because of their weight and low velocity, they have limited range.
• Less lethal, or Less than Lethal: Rubber bullets, plastic bullets, and beanbags are designed to be non-lethal, for example for use in riot control. They are generally low velocity and are fired from shotguns, grenade launchers, paint ball guns, or specially-designed firearms and air gun devices.
• Incendiary: These bullets are made with an explosive or flammable mixture in the tip that is designed to ignite on contact with a target. The intent is to ignite fuel or munitions in the target area, thereby adding to the destructive power of the bullet itself.

Lead alloy bullets as cast (left), with gas check (center) and lubricated (right).

• Exploding: Similar to the incendiary bullet, this type of projectile is designed to explode upon hitting a hard surface, preferably the bone of the intended target. Not to be mistaken for cannon shells or grenades with fuse devices, these bullets have only a cavity filled with a small amount of low explosive depending on the velocity and deformation upon impact to detonate.
• Tracer: These have a hollow back, filled with a flare material. Usually this is a mixture of magnesium metal, a perchlorate, and strontium salts to yield a bright red color, although other materials providing other colors have also sometimes been used. Tracer material burns out after a certain amount of time. Such ammunition is useful to the shooter as a means of learning how to point shoot moving targets with rifles. This type of round is also used by all branches of the United States military in combat environments as a signaling device to friendly forces. Normally it is loaded at a four to one ratio with ball ammunition and is intended to show where you are firing so friendly forces can engage the target as well. The flight characteristics of tracer rounds differ from normal bullets due to their lighter weight.
• Armor piercing: Jacketed designs where the core material is a very hard, high-density metal such as tungsten, tungsten carbide, depleted uranium, or steel. A pointed tip is often used, but a flat tip on the penetrator portion is generally more effective.^[3]
• Non toxic shot: Steel, bismuth, tungsten, and other exotic bullet alloys prevent release of toxic lead into the environment. Regulations in several countries mandate the use of non-toxic projectiles especially when hunting waterfowl. It has been found that birds swallow small lead shot for their gizzards to grind food (as they would swallow pebbles of similar size), and the effects of lead poisoning by constant grinding of lead pellets against food means lead poisoning effects are magnified. Such concerns apply primarily to shotguns, firing pellets (shot) and not bullets, but reduction of hazardous substances (RoHS) legislation has also been applied to bullets on occasion to reduce the impact of lead on the environment at shooting ranges. United States Environmental Protection Agency announced that the agency does not have the legal authority to regulate this type of product (lead bullets) under the Toxic Substances Control Act (TSCA), nor is the agency seeking such authority. NRA-ILA :: EPA Denies Ammo Ban Petition
• Blended-metal: Bullets made using cores from powdered metals other than lead with binder or sometimes sintered.
• Frangible: Designed to disintegrate into tiny particles upon impact to minimize their penetration for reasons of range safety, to limit environmental impact, or to limit the shoot-through danger behind the intended target. An example is the Glaser Safety Slug.
• Solid or Monolithic Solid: mono-metal bullets intended for deep penetration in big game animals and slender shaped very-low-drag projectiles for long range shooting are produced out of metals like oxygen free copper and alloys like copper nickel, tellurium copper and brass like highly machinable UNS C36000 Free-Cutting Brass. Often these projectiles are turned on precision CNC lathes.

Treaties and prohibitions

The St. Petersburg Declaration of 1868 prohibited the use of explosive projectiles weighing less than 400 grams.^[4]

The Hague Convention prohibits certain kinds of ammunition for use by uniformed military personnel against the uniformed military personnel of opposing forces. These include projectiles which explode within an individual, poisoned and expanding bullets.

Protocol III of the 1983 Convention on Certain Conventional Weapons, an annexe to the Geneva Conventions, prohibits the use of incendiary munitions against civilians.

Nothing in these treaties prohibits tracers or the use of prohibited bullets on military equipment.

These treaties apply even to .22 LR bullets used in pistols, rifles and machine guns. Hence, the High Standard HDM pistol, a .22 LR suppressed pistol, had special bullets developed for it during World War II that were full metal jacketed, in place of the soft-point and hollow-point bullets that are otherwise ubiquitous for .22 LR rounds.

Some jurisdictions are acting on environmental concerns and banning hunting with lead shotgun pellets. This creates issues for shooters because stainless steel pellets are considered to behave sub-optimally in flight compared to lead. The element bismuth is a safe alternative whose atomic mass is closer to lead than steel, and ammunition made from it is becoming ever more widely available.

Bullet abbreviations

2F – 2-part Controlled Fragmenting ACC – Remington Accelerator [5] (see sabot) ACP – Automatic Colt Pistol AE – Action Express AGS – African Grand Slam (Speer) AP – Armor Piercing (has a steel or other hard metal core) APT – Armor-piercing tracer API – Armor-piercing incendiary APFSDS – Armor-piercing Fin Stabilized Discarding Sabot round B – Ball B2F – Brass 2-part Fragmenting [6] BBWC – Bevel Base Wadcutter BEB – Brass Enclosed Base BJHP – Brass Jacketed Hollow Point Blitz – Sierra BlitzKing BMG – Browning Machine Gun BrPT – Bronze Point Bt – Boat-tail BtHP – Boat-tail Hollow Point C2F – Civilian 2-part Fragmenting [7] CB – Cast Bullet CL, C-L – Remington Core-Lokt CN – Cupronicknel CNCS – Cupronickel-Clad Steel CTFB – Closed Tip Flat Base DBBWC – Double bevel based wadcutter DEWC – Double Ended Wadcutter DGS – Dangerous Game Solid (Hornady) DGX – Dangerous Game Expanding (Hornady) DU – Depleted Uranium EVO, FTX – Hornady LEVERevolution Flex Tip eXpanding EVO – RWS Evolution bullet [8] FMC – Full Metal Case FMJ – Full Metal Jacket FMJBT – Full Metal Jacket Boat-Tail FN – Dangerous Game Solid Bullets Flat Nose FNEB – Flat Nose Enclosed Base FP – Flat Point FP – Full Patch FST – Winchester Fail Safe Talon GC – Gas Check GD – Speer Gold Dot GDHP – Speer Gold Dot Hollow Point GM – Gilding Metal GMCS – Gilding Metal-Clad Steel GS – Remington Golden Saber GSC – GS Custom Turned Copper Bullets HBWC – Hollow Base Wadcutter HC – Hard Cast HE-IT – High Explosive Incendiary Tracer HP – Hollow Point HPBT – Hollow Point Boat Tail HPJ – High Performance Jacketed HS – Federal Hydra-Shok HST – Federal Hi-Shok Two

HV – Low friction Drive Band Bullets High Velocity ID-Classic – RWS fragmentation bullet, ex-TIG after Brenneke-license was not renewed.[9] I-T – Incendiary-Tracer 'IB – Interbond (Hornady) J – Jacketed JAP – Jacketed Aluminium Point JFP – Jacketed Flat Point JHC – Jacketed Hollow Cavity JHP – Jacketed Hollow Point JHP/sabot – Jacketed Hollow Point/sabot JSP – Jacketed Soft Point L – Lead L-C – Lead Combat L-T – Lead Target LFN – Long Flat Nose LFP – Lead Flat Point LHP – Lead Hollow Point LRN – Lead Round Nose LSWC – Lead Semiwadcutter LSWC-GC – Lead Semiwadcutter Gas Checked LWC – Lead Wadcutter LTC – Lead Truncated Cone MC – Metal Cased MHP – Match Hollow Point MK – Sierra MatchKing MRWC – Mid-Range Wadcutter MP – Metal Point (only the tip of the bullet is covered) NP – Nosler Partition OTM – Open Tip Match OWC – Ogival Wadcutter [10] P – Pracitce, proof PB – Lead Bullet PB – Parabellum PL – Remington Power-Lokt PnPT – Pneumatic Point PPL – Paper patched lead PSP – Plated Soft Point PSP, PTDSP – Pointed Soft Point

RN – Round Nose RNFP – Round Nose Flat Point RNL – Round Nosed Lead SJ – Semi-Jacketed SJHP – Semi-Jacketed Hollow Point SJSP – Semi-Jacketed Soft Point SP – Soft Point SP – Spire Point Sp, SPTZ – Spitzer SPC – Special Purpose Cartridge SpHP – Spitzer Hollow Point SST – Hornady Super Shock Tip SSp – Semi-Spitzer ST – Silver Tip STHP – Silver Tip Hollow Point SWC – Semiwadcutter SX – Super Explosive SXT – Winchester Ranger Supreme Expansion Technology T – Tracer TAG – Brenneke lead-free bullet (German: Torpedo Alternativ-Geschoß)[11] TBBC – Carter/Speer Trophy Bonded Bear Claw soft point TBSS – Carter/Speer Trophy Bonded Sledgehammer Solid TC – Truncated Cone THV – Terminal High Velocity TIG – Brenneke fragmentation bullet (German: Torpedo Ideal-Geschoß)[12] TMJ – Total Metal Jacket TNT – Speer TNT TUG – Brenneke deformation bullet (German: Torpedo Universal-Geschoß)[13] TOG – Brenneke deformation bullet (German: Torpedo Optimal-Geschoß)[14] UmbPT – Umbrella Point UNI-Classic – RWS deformation bullet, ex-TUG after Brenneke-license was not renewed.[15] VMAX – Hornady V-Max VLD – Very Low Drag WC – Wadcutter WFN – Wide Flat Nose WFNGC – Wide Flat Nose Gas Check WLN – Wide Long Nose X – Barnes X-Bullet XTP – Hornady Extreme Terminal Performance

Figurative uses

The word for the bullet, usually because of its speed, is sometimes used figuratively, e.g.:

• The Japanese Bullet Trains.
• The 350cc Royal Enfield motorcycle marketed in India is called Bullet
• The expression "bullet-headed" for a dolichocephalic shape of an animal's head.
• The term silver bullet, an extremely effective solution to a problem, comes from the modern addition to werewolf folklore that the monster is highly vulnerable to firearms using silver ammunition.
• The phrase "biting the bullet", meaning (usually mental) preparation for an unpleasant task or experience, refers to a patient biting on a lead bullet put between his back teeth to brace himself for a painful medical procedure (such as the removal of a bullet or amputation of a limb) before the advent of anesthesia. This was frequently done on or behind a battlefield, where bullets would be readily available.
• In horse racing, each track marks its fastest training session each day with a bullet in that horse's past performances.
• In motion pictures (including television, narrative film and motion pictures and gameplay within videogames), bullet time is a digitally enhanced shot in which, first, the film's speed is reduced to extreme slow motion or, sometimes, to a static frame, and then, second, the camera rotates around the scene at normal speed, providing the viewer with a glimpse of the action from many different angles. Bullet time allows the viewer to capture action s/he would not be able to see in detail at normal speeds. It also allows the viewer to see this action from many angles that would be otherwise hidden from view. Under normal filming conditions, the person shooting the scene would have to choose one angle from which to shoot the action. Camera rotations in bullet time may vary from a relatively small angle, such as 90°, to a full 360°. The bullet time technique is often used in videogames as a convention that allows the player special abilities, such as the ability to slow down time and gain the advantage from this. The term, "bullet time," was first used in reference to the film, The Matrix, that used this technique to create a slow motion shot of a series of fired bullets in which the camera circled around the bullets and their intended target.
• The expression "catching a bullet in his teeth" comes from reports of sleight-of-hand magician Benjamin Perry Covington, who was said to have caught three bullets in his teeth fired from three different guns fired by volunteers in a New York magic act in the early 1920s.
• The expression "shooting blanks" is used idiomatically to refer to male sterility. A blank round contains no projectile (and thus very little lethality), much like the semen of an infertile man contains no viable sperm.
• In no limit holdem poker, "bullets" is one of the names given to the starting hand of AA; other names include "American Airlines" and "Pocket Rockets".

See also

• Category:Ammunition
• List of handgun cartridges
• List of rifle cartridges
• List of Shotgun cartridges
• Table of pistol and rifle cartridges by year
• Bullet bow shockwave
• Bullet Physics Engine
• Cartridge (firearms)
• Firepower
• Fractography
• Kinetic projectile
• Meplat
• Percussion cap
• Personal armor
• Sabot
• Smart bullet
• Weapon
• Ogive

References

1. ^ The Exploding Bullet Journal of Clinical Pathology
2. ^ RCBS
3. ^ Hughes, David (1990). The History and Development of the M16 Rifle and Its Cartridge. Oceanside: Armory Pub. ISBN 978-0-9626096-0-2. 
4. ^ Glover, William H.. "Purposes and Basic Principles of the Law of War". http://williamhgloverjd.wordpress.com/2009/12/04/purposes-and-basic-principles-of-the-law-of-war/. Retrieved 2010-07-28. 
5. ^ Bullet Basics 1- Materials; Remington Accelerator (at bottom of page)
6. ^ http://www.fsdip.com/website/LinkClick.aspx?link=405&tabid=36
7. ^ http://www.fsdip.com/website/LinkClick.aspx?link=403&tabid=36
8. ^ http://jagd.rottweil-munition.de/en/products/centerfire-rifle-cartridges/bullets/evo.html
9. ^ http://jagd.rottweil-munition.de/en/products/centerfire-rifle-cartridges/bullets/id-classic.html
10. ^ Lead Bullets Technology - Premium Molds
11. ^ http://www.brenneke-munition.de/cms/tag.html?&L=1
12. ^ http://www.brenneke-munition.de/cms/tig.html?&L=1
13. ^ http://www.brenneke-munition.de/cms/tug.html?&L=1
14. ^ http://www.brenneke-munition.de/cms/tog.html?&L=1
15. ^ http://jagd.rottweil-munition.de/en/products/centerfire-rifle-cartridges/bullets/uni-classic.html

 This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press. Template:Http://www.nejm.org/doi/full/10.1056/NEJMicm0801917

External links

Wikimedia Commons has media related to: bullets

• [1]
• "Bullets by the Billion", 1946 - Story about the manufacture of small caliber ammunition during World War II
• Arizona Gun List - ammunition types
• Bullet acronyms and abbreviations with illustrations
• Bullets for Beginners
• Dangerous Game Bullets.
• European Ammunition Box Translations
• [2]
• Remington Core-Lokt, Bronze Point & Power-Lokt Centerfire Ammunition

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - kugle, projektil

Nederlands (Dutch)
kogel, patroon

Français (French)
n. - balle

Deutsch (German)
n. - Kugel

Ελληνική (Greek)
n. - σφαίρα, βόλι, τυπογραφική βούλα

Italiano (Italian)
pallottola

idioms:

• bite the bullet    ingoiare il rospo

Português (Portuguese)
n. - projétil (m)

idioms:

• bite the bullet    sofrer corajosamente algo bastante desagradável

Русский (Russian)
пуля

idioms:

• bite the bullet    стиснуть зубы

Español (Spanish)
n. - bala

Svenska (Swedish)
n. - kula (till gevär el pistol)

中文（简体）(Chinese (Simplified))
子弹

中文（繁體）(Chinese (Traditional))
n. - 子彈

한국어 (Korean)
n. - 탄환, 해고, 작은 공

日本語 (Japanese)
n. - 銃弾, 弾丸, 小球

العربيه (Arabic)
‏(الاسم) رصاصه‏

עברית (Hebrew)
n. - ‮קליע, כדור‬

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