Why do they call it that?

Basic Principles of Cartridge Naming Conventions

By no means is there a "standard" system used by everyone in the industry. There are variations of systems used by different parts of the world, even more specifically different countries and even right down to individual experimenters and inventors themselves.

Make no mistake, this "guide" as I loosely call it is only to help you decipher what is meant when you hear of a 45-110 Sharps, or perhaps a 577/500 3 1/8" Nitro Express. These rules are not set in stone. As a matter of fact, there seems to be a lack of rules in general. However diverse, there are some basic principles and I will do my best to describe them accurately.

Throughout this site, you may notice that I omit decimal points at the beginning of most American-style calibers. I may note a 270 Winchester or a 6.17 Spitfire. I will only place a decimal point into the caliber when it is absolutely required as in the metric caliber above. This again, is not a standard, it is just how I choose to illustrate this site.

Generally, when a cartridge is named the first portion of the name is the caliber - not necessarily the bullet diameter, but a representation of the actual bullet diameter or bore diameter (either the lands or grooves). The second portion of the name may mean many things. It could be the company that introduced the round and marketed it first (270 Winchester). It may be the person who created it (35 Whelen), or it may simply be a provocative name someone dreamed up (7.21 Tomahawk). The second portion may not be any of these things. The 30-06 Springfield is a 30 caliber cartridge introduced in 1906, while the 250-3000 Savage is a .257 caliber bullet propelled at 3000 fps. So as you can see, there are no rules!

With antique (not necessarily obsolete) cartridges the caliber may come first with the second series of numbers describing either the powder charge (in grains) or perhaps the case length. This is characteristic of cartridges that have an origin of blackpowder nature. An example would be a 40-70 Sharps. It is a 40 caliber bullet with 70 grains of black powder.

The British have reinvented "The System" once again. For the most part, they are similar in nomenclature to American cartridges, but they too have some interesting methods of naming. Many times, there are two numbers much like American cartridges, but there are not-so-obvious differences. The first number in the naming can be the original caliber the round was derived from while the second number representing the actual caliber. Let's look at the 450/400 2 3/8" Nitro Express. It is a 400 caliber bullet in a 450 case necked down to accept it. "Hey! Wait a minute! What is this 2 3/8" mumbo jumbo?", you may ask yourself. That is the case length. Here we go again with the inconsistencies.

Wildcats. The name of this group of cartridges itself suggests oddities and most importantly: Cool. Pure Cool. Let's think about that for a minute. The "Wildcatter" takes cartridges that already exist, change them around (sometimes dramatically), and turn them into something we wonder how we lived without. Why, for an instant, would we think that these same creative geniuses that do this would not come up with equally impressive names for their inventions? We would not expect anything less. The 17 Mach IV, 22 CHeetah, 22 Streamliner and the list goes on and on. However not all wildcats are named in such a way. Many times the inventor puts his tag on it as in the 22 Newton or the 338/50 Talbot. Then again the name can be derived from the combination of the caliber and parent cartridge such as the 6mm-284 or the 22/30-30 Improved. Why would we standardize at this point?