Terminology

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Terminology

Post by Daywalker on Fri Dec 31, 2010 5:50 am

This sticky is to help the newcomers in the world of reloading understand what is being talked about within the forum. It has been brought to my attention that there are some members that get lost while reading posts because they are not quite familure with some of the terms that is being used by seasoned handloaders...

I am going to take this information from my Nosler Reloading Book to make sure that all information is precise and correct accordingly to Nosler themselves. I did not place all of the definition from the book. I will be creating other stickies for parts of the case, bullets and powder types.

Annealing : The process by which metal is softened by exposure to heat. Case necks which have become brittle as a result of repeated resizing can be annealed to prevent cracking and yield longer life. Case neck annealing must be done with care to prevent soften of the case head.

Antimony : A metallic element which increases the hardness of lead when combined as an alloy.

Anvil : The part of the primer which offers resistance to the primer compound as the firing pin strkes the primer. In firing, the primer compound is compressed sharply against the anvil and the resulting shearing force sets off the ignition constituents contained in the primer compound.

Ball : A term used by the military to denote bullet. Also used by Olin Industries to describe their spherical powder. (A side note by me, Some handloaders, casters also like to use the term "Pill" for bullets.)

Ballistics : The science and study of projectiles in motion. Divided into three parts: Interior ballistics is used to describe the events which take place from ignition until projectile leaves the muzzle. Exterior ballistics describes the projectile's flight from muzzle to target, and Terminal ballistics is the study of events after the bullet reaches the target.

Ballistic Coefficient : The ratio of a bullet's sectional density to its coefficient of form, used to describe the bullet's effectiveness in overcoming air resistance during flight.

Barrel Cylinder : The gap or space between the cylinder and forcing cone of the barrel in a revolver.

Bearing Surface : The portion of a projectile which comes in contact with the bore.

Bedding : The part of the stock which forms the ontat with the action and/or barrel. The act of fitting the action to the stock.

Belted Case : A cartridge case with a reinforcing belt forward of the extrator Groove, characteristic of most modern "magnum" cartridges.

Berdan Primer: Normally found only in European cartridges, the Berdan Primer requires a protrusion in the bottom of the primer pocket to serve as an anvil.

Bolt : The part of the action which contains the firing pin assembly, extractor mechanism and the locking system.

Bore : The interior of a barrel. When used to desribe a rifled barrel, the diameter before the rifling is cut. Also called "bore diameter"

Bore Sight : The technique of aligning the sights of a rifle with the target by sighting through the barrel.

Boxer Primer : The primer type used in America centerfire ammunition, both sporting and military.

Brass : A common term used by handloaders in referring to emtpy cartridge cases. An Alloy of copper and zinc.

Bullet : The cartridge componant which, when in flight, becomes a projectile.

Bullet path : The vertical distance of the bullet's trajectory above or below the line of sight.

Bullet Puller : Tool used to pull the bullet from a case.

Burning Rate : A relative term used to define the rate at which a powder burns in comparison with other powders in individual cartridges.

Calibers : The nominal diameter of the groove or bore, oftern modified to show the date of adoption (.30-06) or the designer (.257 Roberts), etc. Caliber i expressed either in deimals of an inch (.308") or in metric (7mm) measurements. Rifle or cartridge designations are often merely approximated; for example: .30,.308 and .300 cartridges all use a .308" diameter bullet.

Cannelure : A groove around a bullet that is ued for crimping, lubricating or identification.

Cap : An early form of today's primer, used to ignite black powder charges. The term is still sometimes used to denote primer.

Cartridge : A complete round of ammunition with all components intact.

Case : The salvageable brass component of a cartridge which serves as a container for the expendable components.

Case Trimmer : Tool used for trimming case length back to the original dimension.

Centerfire : A cartridge with the primer located in the enter of the case head.

Chamber : The section of the barrel which encloses the cartridge to restrict case expansion during firing.

Chamber cast : A molding taken of the chamber by pouring a low-melting-point metal or compound into the chamber. The casting permits accurate measurement of critical chamber dimensions.

Chamfer : The process of reaming or beveling a taper on the inside or outside of a case mouth to remove burrs left by the case trimming operation.

Charge : The quanity of powder loaded into a case. Usually expressed in grains and/or tenths of a grain.

Components : The items necessary to load a cartridge (brass, primer, powder, bullet.)

Compressed Charge : A condition where powder is packed mroe densely in a case than would normally occure. Caused by fillingthe case to a point where seating a bullet ccompresses the powder.

Crimp : To turn the case mouth slightly inward, usually into a cannelure, to grip a bullet firmly.

Deburr : To remove the rough and jagged edges left when a case is trimmed to length.

Decap (Deprime) : To eject the spent primer from the pocket of a fired case.

Die : In reloading, a tool used to re-form a fired brass case or to seat a gresh bullet into the case mouth. In bullet making, a tool used to form the bullet.

Drift : A term used in exterior ballistic to describe the deviation of a projectile laterally from the line of departure. Caused by the projectile's rotation.

Drop : The effect of gravity on the projectile. The distance between the line of departure and the trajectory at a given distance.

Energy : In ballistics, the amount of work a projectile is capable of accomplishing. Usually measured at the muxxle and as remaining energy at variou distances from the muzzle.

Epander Ball : A thicker section of the decapping stem, used to expan the case mouth to the precise diameter required to hold the bullet firmly.

FPS : Feet per Second. The masurement used to describe the velocity of the projectile.

Fire Forming : Firing othe cartridge to ahieve full expansion of the as to the dimensions of the chamber.

Flash Hole : An opening that provides access through the web for the primer flash to ignite the powder granules in the case interior.

Foot Pound : A unit of energy. The force required to lift one pound of weight to a height of one foot.

Grain : The weight unit used in measuring powder charges or bullet weights. One pound avoirdupois is equal to 7,000 grains. 435.5 grains is equivalent to one ounce.

Grooves : The spiral cut that is removed from the bore to leave the "lands" The grooves of a .30 caliber rifle are approximately .308" in diameter.

Hangfire : A condition where ignition is delayed after the strike of the firing pin.

Headspace : In handloading, the slight gap that is permitted between the bolt face and the case head to facilitate closure of the bolt. Headspace is actually the distance between the bolt face and the part of the chamber that acts as the cartridge stop.

Ignition : The initial combustion of the powder caused by the flame of the primer.

Jacket : The outer covering of a bullet that is used to contain the lead core and improve the "mushrooming" characterisitics. Gilding metal is considered best for this purpose.

Keyhole : The keyhole shaped print of the bullet on the target which indicates it was not stabilized.

Lands : The raised portion of the spiral rifling that remains after the groove cuts have been made.

Locking Lugs : Protrusions on the bolt that engage a mating reess inside the reciever ring when the bolt is closed. This feature prevents the bolt from moving rearward when the rifle is fired.

Lock Time : The elapsed time between release of the firing pin and it's strike on the primer.

Magnum : A firearm or cartridge case capable of greater power than is normal for the bullet diameter.

Meplat : THe diameter of the blunt section of a bullet tip.

Metal Fouling : Metal deposited from the projectile as it passe through the bore. This condition is not common with bullet jackets constructed of gilding metal.

Micrometer : A caliper - type instrument used to measure thickness or diameter.

Minute of Angle (MOA) : A unit of angular measurement equal to 1/60th of a degree. Usually approcimated as 1" (actually 1.047") at 100 yards, 2" at 200 yards, etc.

Muzzle : The end of the barrel where the projectile leaves the bore.

Muzzle Energy : The energy of a projectile, measured in foot pounds, at the muzzle.

Muzzle Velocity : The velocity of a projectile, usually measured in fps, at the muzzel.

Neck Reaming : A technique used to achieve uniform case wall thickness at the neck by removing metal from the inside of the case mounth.

Neck Sizing : A resizing technique in which only the neck portion of the case is sized.

Neck Turning : A technique used to achieve uniform case wall thinckness at the nexk by removing metal from the outside of the case wall.

O.A.L : Overall Cartridge Length

Ogive : The curved, forward portion of a bullet

Pierced Primer : A primer that has been punctured, usually by a defective firing pin.

Point of Aim : The point where the bullet path intersects the line of sight.

Primer Pocket : A recess in the head of a centerfire cartridge case which holds the primer.

Protruding Primer : A primer that has partially backed out of the primer pocket.

Ram : The section of a reloading press, supporting the shellholder, which is used to raise or lower the case into the die during resizing and bullet seating.

Rifling : Parallel spiral groove, cut into the bore of the firearm, which impart a spin to the projectile.

Round : A completely assembled cartridge with all componants unused.

Rupture : A split or seperation in the case wall or neck.

Sectional Density : The ratio of a bullet's weight, in pounds, to the square of it's diameter, in inches.

Shank : The cylindrical, straight section of a bullet behind the ogive.

Shellholder : The device that holds the case upright and guides it into the die cavity. A given cartridge requires a shellholder of a specific size.

Spent primer : A primer that has been fired and in which the priming compound has been expended.

Swaging : A process used to form a material under pressure.

Throat : The unrifled section of the bore immediately ahead of the chamber.

Twist : The rate of spiral of the rifling. Given as the barrel length required to make one full revolution: i.e, "One Turn in Ten Inches," etc.

Velocity : The speed of a projectile in flight. Usually measured in fps at a specific distance.

Wildcat : A cartridge that is not commercially available. Produced from standard cases through the use of special forming dies, the altered case must be fire-formed in the chamber of the rifle to complete the reforming process.

Wind Deflection : A lateral change in bullet trajectory caused by crosswind.


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Re: Terminology

Post by Daywalker on Fri Dec 31, 2010 6:36 am

Feel free to add other Terms that I may have missed that you feel will also help new reloaders to understand what is going on so they do not feel as lost.

Thanks..

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