For someone new to firearms and ammunition, it can be confusing to understand the different names and terms given to ammunition cartridges. There are several types and shapes of ammunition, and knowing the difference can make a big impact on the safety and performance of the firearm.
The confusion is brought about by the absence of a naming standard. Generally, the numbers used in ammunition indicate the metal bullet’s diameter. Therefore, a .45 means that it is .45 of an inch in diameter while the diameter of a .22 is .22 of an inch.
The compound number used to describe ammunition represents diameter to length ratio, such as:
- 56×45 mm – 5.56mm wide, 45mm long
- 9×19 mm – 9mm wide, 19mm long
Shotshells on the other hand are measured in gauge. The larger diameter is the lower number. A 12-gauge shell is 70mm in length, which is about 2.5 inches. It is also available in 3-inch magnum.
Components of a cartridge
A cartridge is the type packaging of small arms ammunition, which is composed of four parts:
- Case – which is typically made of steel, nickel or brass
- Primer – the propellant’s ignition. It is the round dimple located at the cartridge’s base.
- Propellant/powder – the gunpowder
- Projectile – the actual bullet
A cartridge with propellant but without a bullet is called a blank. A dummy or drill round does not have a primer, propellant and bullet, and typically used for training purposes and when checking the performance of a firearm. A dummy round is also called a snap cap.
Types of cartridges
As there are several types of firearms, there are also different types of cartridges that are loaded into them. The types include the following:
- 8mm Mauser (actually 7.9mm)
- 12 gauge Shotshell
- .22 Long Rifle
- 45x39mm Soviet
- 56x45mm NATO (.223 Remington)
- 62x39mm Soviet
- 62x51mm (.308 Winchester)
- 62x54mm Russian (rimless base)
- .44 Magnum (rimless base)
- .45 Automatic Colt Pistol or ACP
- 9x19mm Para. (also called Parabellum, Luger or just 9mm, but they slightly vary in length)
What is a caliber?
Caliber or calibre, (abbreviation – cal.) is the estimated diameter of the internal part of the gun’s barrel. It also represents the diameter of the projectile or the bullet. A .45 caliber gun for example means that the barrel diameter measures .45 of an inch or close to but still not quite half an inch.
Diameters can be expressed in metric as well, such as 9mm guns. The decimal point is typically dropped when said orally, but included in written descriptions.
Here are examples of the typical naming conventions, to make it easier for you to understand the caliber of the ammunition (ammo).
- 30-06 – the first number represents the caliber of the ammo, while 06 represents the year 1906 (standard rifle cartridge of the U.S. military)
- 270 Winchester – approximate diameter of the bullet (actual size – .277-inch); Winchester is the manufacturer that standardized this type of ammo.
- 375 H&H Magnum – bullet diameter = .375-inch; H&H stands for Holland & Holland, a British manufacturer; magnum is the name given to the ammo because it is slightly bigger than its counterparts
- 220 Swift – about .224″ in diameter; swift is added because it is exceedingly fast (also manufactured by Winchester)
- 45-70 Government – officially adopted for the use of the U.S. government; size is .458″
- 30-30 Winchester – first number is its diameter while the second number represents its 30 grains of black powder load.
- 45 ACP – the ’45’ represents the diameter of the bullet while ACP refers to the original gun, the Automatic Colt Pistol model 1911.
Types of bullets
The projectile or the bullet, which is the actual piece that flies out of a firearm, comes in different types, which are usually called by their acronyms, as follows:
- LRN – Lead Round Nose
- WC – Wad Cutter
- SWC – Semi Wad Cutter
- SJ – Semi Jacketed
- SJHP – Semi Jacketed Hollow Point
- JHP – Jacketed Hollow Point
- FMJ – Full Metal Jacket
- SP – Soft Point (not coating on bullet tip, exposing the lead)
- AP – Armor Piercing (alloy core)
- BT – Boat Tail (cartridge’s read end is tapered for flight stability of the projectile)
- BTHP – Boat Tail Hollow Point
- RBCD – Special (the acronym is the name of the manufacturer)
Ammunition nomenclature is definitely confusing. The important thing to remember is to have the appropriate ammunition and protection for your firearm. The diameter should perfectly match the size of the gun’s barrel to have the right seal.
With the market flooded with different makers, you need to be specific when you purchase your cartridges. A common 7.62 could be for a 7.62×59, 7.62×54 Russian, 7.62×54 Russian, 7.62×39 Soviet or a 7.62×25 Tokarov.
Contributor: Imran Khan