Centerfire Rifle Cartridges:
Written by: Kim Lockhart, Copyright.
Centerfire Rifle Cartridges And Ballistics:
The centerfire rifle cartridge is a type of rifle ammunition that has a bullet as a projectile that is fired from a breech loading rifle. The components consist of a piece of brass or cartridge case that contains a rifle powder propellant charge, a primer that ignites the powder charge after being struck by the rifles firing pin and a bullet which is expelled out the muzzle end of the breech loading rifles barrel, by means of the expanding gases of the ignited rifle powder. The action of the bullet once leaving the rifle barrel is usually refered to as external ballistics.
The centerfire rifle cartridge is reloadable with the use of reloading equipment and is more accurate than factory ammunition when accuracy reloading guidelines are followed.223 Remington - 243 Winchester - 25-06 Remington - 270 Winchester
7mm Rem. Mag. - 30-30 Win. - 308 Win. - 30-06 Sprg. - 300 Win. Mag.
Rifle Cartridge Brass: The main identifiable parts of a cartridge case are: mouth, neck, shoulder, body, head, web, flash hole, rim and primer pocket. In the head area of the cartridge case there are four designs and they are: rimmed, belted, rimless and rebated.
Rifle cartridge cases consist of approximately 70% copper and 30% zinc combined metals and is the fundamental reloading component that does not get spent in the firing process of a centerfire rifle cartridge. The cartridge casings main function is to seal the chamber area of the rifle barrel preventing high pressure gases from getting past the cartridge case in the chamber. The reason for using brass for the cartridge case is that it will expand readily and make a seal. There are two case shapes of brass cartridge cases, straight wall and bottle neck, the bottle neck cases neck and bullet diameter are smaller than the case body diameter.
Rimmed Cartridge Cases: Headspace in the rifles chamber on the rim portion of the cartridge case.
Rimless, Semi-Rimless and Rebated Cartridge Cases: Headspace in the rifles chamber on the shoulder portion of the cartridge case.
Belted Cartridge Cases: Headspace in the rifles chamber on the raised belt portion of the cartridge case.
Rifle Cartridge Primer:
The centerfire rifle cartridge is aptly named because the cartridge ignition source is a primer located in the center of the cartridge casings web. The type of primer used in American manufactured ammuntion is boxer, which have an internal anvil and small explosive charge that when struck by a firing pin ignites, the flame travels through the flash hole in the cartridge case web and enters the case body where the main powder charge is then ignited. The two standard primer sizes for metallic centerfire rifle cartridges are small rifle which are .175" diameter and large rifle which are .210" diameter. The two distinct heat ranges of primers are standard and magnum. Magnum primers are used to ignite large powder charges normally associated with a magnum cartridge case.
Rifle Cartridge Powder:
Modern smokeless powder once ignited produce expanding gases that push the bullet down the rifles bore giving us a certain amount of velocity to our bullet. Modern smokeless powders come in two types, single base nitrocellulous and double base nitrocellulous with the addition of nitroglycerine. Modern smokeless rifle powder have various shapes and they are, extruded or tubular, ball or spherical, round flat flake and diamond flat flake.
Rifle Cartridge Bullet:
Rifle bullet caliber is the outside diameter of a bullet that fits the maximum inside diameter of a rifles rifled bore in the rifling grooves, expressed in hundredths or thousandths of an inch and typically written as a decimal fraction such as; .17", .20", .22", .24", .25", .26", .27", .28", .30", .31", .32", .33", .35", .37", .41", .43", .45", .51".