Ammunition Types
Cartridge ammunition can be broken into two main categories. Rimfire and Centrefire. Both types of ammunition can be used in either rifles or handguns. Modern shotshells are all centrefire.
The picture to the left shows a .22 rimfire cartridge. In the past rimfire cartridges were as large as .44 calibre however, today rimfires are most commonly of .22 calibre. Note the bulbous rim at the base of the cartridge. The priming compound (impact sensitive material) is inside the cartridge case, in the rim. The firing pin hits the rim of the brass case, crushing it and activating the priming compound which in turn ignites the powder.
The bullet is of non-jacketed lead construction. The copper colour is from a copper wash. Some .22 Magnum cartridges use jacketed bullets.
All rimfire cartridges are considered to be low powered, even if they are named "magnum".
The image to the right shows typical centrefire rifle cartridges. Note the large, centrally located primer in the base of the cartridge. It is the primer that is hit by the firing pin, thus beginning the chain of events that results in the bullet being pushed out of the barrel by high pressure gases created by the burning gunpowder.
Centrefire cartridges are used in all high pressure (read - high powered) handguns and rifles.
Ammunition Components
All conventional ammunition is made up of four components. These are the brass case, primer, powder and bullet.
The brass case holds the other three components (primer, powder & bullet) together in their proper places. It also acts as a gasket to seal the high pressure gasses inside the chamber during firing. The action/receiver of the firearm cannot contain the pressure, which can exceed 50,000 psi in a rifle.
Centrefire cartridges can be reloaded and used, usually many times, by removing the dead primer and inserting a live one, and then adding a new charge of powder and a new bullet.
Cases come in many different types like: Rimmed, semi-rimmed, rimless (picture to right), rebated rim, belted, straight wall (picture to right), rifle (incorporates a shoulder and neck [picture above])
The primer is a small device containing three parts (Cup, Anvil and Primer Pellet). The cup is the part you can see in the base of a centrefire cartridge. The metal cup contains the explosive priming compound and the metal anvil. When struck by the firing pin, the primer pellet is crushed between the dented cup and the anvil. The priming compound is very sensitive to impact and when struck it explodes in a flash of fire. The flame then ignites the powder charge.
There are two common types of centrefire primers; Boxer and Berdan. The primers pictured here are all of the Boxer type. Berdan primers are mostly used in military surplus and European manufactured ammunition.
Right Image: (Left to Right) Boxer primers: Spent primer - bottom, anvil, spent primer - top, cup, new primer.
Left Images: Diagrams of Boxer and Berdan Primers.
There are two types of gunpowder: Black powder and smokeless powder. Black powder is a mixture of three chemicals(charcoal, sulfur and potassium nitrate [saltpetre]), and is a low explosive that produces large volumes of white smoke when ignited. Smokeless powder is one chemical. It decomposes into relatively smoke-free hot gases when ignited, and is a flammable solid, not an explosive.
Blackpowder is all of the same formulation, it is simply divided up by the granulation size from largest to smallest (Fg to FFFFg). The smaller grains burn faster, so they are used for small calibre firearms and for priming flintlocks. The larger-grained slower-burning powders are used in large calibre muskets, rifles and shotguns.
There are dozens of different types (formulations) of smokeless powders and they come in many different sizes and shapes. The image to the right shows a typical "stick" or extruded rifle powder. Smokeless powders can be extruded sticks, balls or flakes.
Bullets can be made out of nearly any dense metal. However the most common material is lead. Some handgun bullets may be cast lead while most rifle bullets are a lead core surrounded by a copper jacket. The copper jacket allows much higher velocities without the problem of the soft lead being stripped off and deposited in the barrel. Bullets come in hundreds of shapes and sizes, even within a specific calibre. The size and shape depends on the task the bullet is to perform.
Did you know? One misconception about hollow point bullets is that they "explode" inside the target causing a shredding effect. The image to the right shows what a hollow point bullet looks like after impact. While the bullet does expand greatly, it does not lose more than 5-10% of its mass in the process. A bullet that did fall apart would not penetrate deep enough.
Did you know? There is a myth of "cop killer bullets" that can penetrate body armour and then expand to kill the officer wearing it. This is pure fantasy. A bullet can be designed to penetrate armour or it can be designed to expand in soft tissue. It CANNOT do both. The "teflon" coating on the much maligned Black Talon ammunition is simply an aid to reducing barrel fouling in the handgun. It does nothing to enhance the bullet's ability to penetrate body armour. Many hunting bullets are coated with different compounds these days.
More information on Armour Piercing Ammunition
Shotshells
Shotshells are similar to other centrefire cartridges but with a couple of important differences.
Shotshell primers work the same as a Boxer primer but they look different and are much larger.
Shotshell cases are called "Hulls" because they are made of plastic with a brass head. Older hulls were made of paper or solid brass.
Because of the nature of the projectile (lead or steel pellets), a shotshell has a plastic or paper wad to contain the shot as a unit until it exits the barrel. At that point the wad falls away and the shot continues forward.
Cartridge Names
The subject of cartridge names is enough to give even the most easy going person a few grey hairs. Cartridge names follow few if any rules and in many cases names are either totally out of date or they have nothing to do with the actual cartridge dimensions. To add to the confusion some cartridges go by multiple names depending on where you are.
There is simply no option but to dive in and learn cartridge names. With a bit of experience the various names become somewhat manageable but even us experts get caught flat footed on a regular basis.
Cartridge names originate from a variety of different sources. There are names of American as well as European origin. There are names applied by the ammunition factories and there are wildcat (experimental or independent catridges) names coined by the creators. There are military and civilian names and there are new names and old names.
To avoid driving you nuts with reams of weird numbers and names, we will cover some of the more common cartridges and ones with multiple names as examples. If you have any questions please feel free to contact us.
Example #1: Possibly the most common rifle cartridge in North America, the .30-06 Springfield is typical in that its name comes from an impossibly archaic combination. The first part ".30" stands for the nominal calibre of the bullet. ie This is a .30 calibre cartridge. The "06" is the year (1906) that this cartridge was adopted for use by the US Military. Springfield comes from the '03 Springfield rifle which was the first rifle it was chambered in. Originally the .30-06 was named the .30-03 because it was adopted for use in the 1903 Springfield rifle. A few changes were made to the cartridge in 1906 and the new name was adopted to avoid confusion with the old version.
Example #2: The 9mm Parabellum is but one of an entire family of 9mm cartridges. The 9mm Parabellum is a German designed and named cartridge. However over time the name "9mm" has been universally adopted as the name for this particular cartridge. The newer designation of 9x19 is beginning to see use in order to reduce confusion with other similar cartridges (ie 9x21, 9x23 etc). There are probably a dozen other "9mm" cartridges that use different names to distinguish them in their own right.
As a side note to the 9mm, we should quickly discuss the .380 ACP (Automatic Colt Pistol) cartridge. The .380 goes by several different names around the world. .380 ACP is the American designation but it can also be called the 9mm Short. In Europe this cartridge goes by the name 9mm Kurtz.
Did you know? How different names for the same cartridge affect us here on one continent? Try and purchase 9mm Kurtz ammo, for a European built handgun, in North America and you will soon discover how it affects us.
Example #3: The .45 LC (Long Colt) cartridge is very common in cowboy action shooting in North America. Amazingly there was never a .45 Short Colt. The proper name for the .45 LC is actually .45 Colt. The "Long Colt" name was adopted to avoid confusion with the .45 ACP (Automatic Colt Pistol) cartridge which is also commonly referred to as the .45 Colt.
Example #4: The 45-70 Government name is derived from two physical dimensions of the cartridge. That being the calibre of the bullet (.45 calibre) and the amount of blackpowder in the case. This cartridge was designed in the time of blackpowder (when there was only one type of powder) and it commonly used a powder charge of 70 grains. A "grain" is a measurement of weight. There are 7000 grains in a pound. The Government part of the name is derived from the fact that this cartridge was official government issue to the US Army from 1873 to 1892.
This type of name combination is common in old blackpowder cartridges and is seen in the 25-20, 44-40, 38-40, 45-90 etc.
Example #5: When one cartridge is made from another one (wildcat) sometimes part of the old name remains. This is the case for the 22-250 Remington. This cartridge was made by necking down the older 250-3000 cartridge. Originally named the .22 Varminter, the name 22-250 Remington was applied by the Remington factory when the cartridge was legitimized as a factory loading.
Did you know? The name of the original 250-3000 referred to the nominal calibre (.25 calibre) and the top velocity of the cartridge 3000 feet per second (1950 mph). This was one of the first cartridges to break the 3000 fps barrier and the accomplishment has been immortalized in its name.
Example #6: In some cases the name of the cartridge's designer has been incorporated into the name of the cartridge. This is the case for the 6PPC (Palmisano Pindel Cartridge) which was designed by Dr Palmisano and Mr Pindell. All of the Weatherby cartridges are named after their designer Roy Weatherby. The 257 Roberts is a .25 calibre cartridge developed by Ned Roberts. As well this holds for any cartridge bearing the names Mauser, Savage and Marlin.
Example #7: Modern military cartridges bear probably the least confusing names. Modern convention has dictated a two part name, the first part being the calibre in millimeters and the second being the length of the cartridge in millimeters. This has lead to names like 7.62x39, 5.56x45, 6.5x55 etc. Even so there is still some confusion when military cartridges are adopted for civilian use, as is the case for the 7.62x51 and .308 Winchester which are the same cartridge.
Did you know? While the 7.62x51 and .308 Winchester have the same outside dimensions, military cases are usually thicker than commercial cases. Therefore a reloader must be careful to note which type of cases are being used. Military cases may cause excessive pressure when reloaded with a powder charge that would be safe in a commercial case.