Have you ever stopped to think about exactly how many ammunition calibers there are?
If you go to a local gun store or ammunition website, you’ll find a plethora of calibers available.
The remarkable thing about that is there are far more possibilities available than what most places carry or keep on hand.
It makes sense that there would be more possibilities beyond what you tend to see.
Most stores and online retailers deal only in the most common calibers based solely on economics. Even places that do keep some of the more obscure stuff in stock usually don’t have much of it.
It doesn’t make sense to have crates of 28 Nosler sitting around when your customers are buying 9mm.
What’s even more interesting is that, despite this, there are still new caliber offerings being developed all the time.
Even variants of existing types of rounds find their way onto the scene periodically. Some of them become quite popular, and some of them don't. But why does this happen?
Why are people still creating or modifying calibers when so many already exist?
The History of Calibers
In the early days of firearms, rounds were developed and created to meet the needs of the people who created them.
As the popularity of firearms grew over time and they became increasingly integrated into people’s lives, calibers were developed as improvements from existing rounds.
Firearms progressed from the earliest versions — literal hand cannons — to become the muzzle loading muskets of a few hundred years ago.
From there, technological advancements caused muskets to progress from smoothbore guns with round ball ammunition to rifles and handguns with cartridges.
In many cases, these new guns were originally developed as improvements to the existing models, so the calibers would be produced the same way despite changes to the operation of the guns.
But technological advancements continued. As the guns improved, so did our understanding of ballistics and accuracy.
As such, new guns began to emerge in new calibers that would better take advantage of the increasingly modern production techniques.
All of this happened while older calibers were still being produced.
Creativity and Caliber
Many entrepreneurs, engineers and tinkerers found themselves smitten with the idea of creating a new style of firearm or bullet.
During this time of expansion in the development of guns and ammo, many people tried their hand at creating new firearm devices.
People got creative with everything from mechanical operation to new cartridges and loading procedures. In many instances, these attempts at creativity brought with them new calibers.
Just as before, the old styles continued to be popular and hang around as new calibers were developed and entered the market, further expanding offerings.
Sometimes, these new calibers were made out of necessity. New patents on specific kinds of loading ports and breeches required new kinds of cartridges.
Some were more about marketing. If you're creating a new way to load a weapon and want to make it seem that much more special, why not also create a new kind of round that will fit it?
These kinds of patented and exclusive cartridge and gun tandems became selling points and marketing gimmicks for many companies.
Specialty Use Calibers
Pure creativity isn’t the only reason this happened, though. Sometimes rounds were created for specific uses.
As America’s expansion west and world exploration (and the early stages of globalization) began, people began to need guns for specific purposes. Different calibers were created for those intended uses.
Calibers suited to chasing off varmints and small predators as well as calibers large enough for those on safari to kill elephants were developed.
Not all were for hunting or defensive purposes, though.
Some rounds were developed for trick shooting or other entertainment purposes, such as those developed for even greater accuracy or speed.
Filling the Void
As all of this was going on, markets continued to adapt, absorbing many new calibers while very few went away.
But interestingly enough, there were many new calibers that were either not well suited to how they were being used or simply didn't perform as intended.
As a result, yet more calibers were developed to fill the void.
It was at this point that people saw the necessity of developing more purpose-specific calibers, and many of these are the forerunners of calibers we have today.
With this also came improvements to older rounds, making them able to shoot farther, penetrate better or just perform better in general. Some of these matched the older calibers in dimensions but now contained new powder loads.
Further still, as time went on, powder improvements, especially the development of smokeless powders, meant that rounds could be even more powerful while taking up less space.
Large rounds with small shell casings and powder loads, small rounds with large loads and everything in between became more readily available. Finally, some manufacturers began to standardize.
This also created variants on rounds, which also became completely new offerings. Standardization and purpose-driven development expanded the number of calibers almost exponentially.
Calibers like the .300 AAC Blackout and 6.5 Creedmoor are excellent examples of this.
These rounds were built from the ground up to fill gaps left by other rounds. They are the epitome of calibers designed to fill specific voids that people within the industry felt needed addressing.
The 6.5 Creedmoor was specifically developed to be very low recoil while being able to travel long distances and still deliver energy into the intended target.
Essentially, it was designed to fill the void of a round that is powerful and accurate at great distances without taking off your shoulder when you shoot it.
Similarly, the 300 AAC Blackout was designed with the intent of being a more capable round for shooting with a suppressor while still fitting into the same space as the standard military arms.
It was designed to deliver the ballistic effectiveness of a 7.62 round while being closer in size to the 5.56 — and to do this after having been fired from a suppressed rifle.
If that doesn’t meet the definition of filling a void, nothing does.
Military Requirements and Calibers
New tactics, new armor and the outbreak of various wars across the globe meant that militaries kept requiring new and improved weapons.
These new weapons often meant new calibers too.
Gun manufacturers scrambled to deliver new offerings that would fit the military’s needs.
Some of the new calibers were reworked versions of older styles and others were genuinely new. Some replaced calibers which already existed and more carved out their own niche.
The most popular rounds in the firearm world today are all the result of development for military use.
While some of the rounds were technically in existence prior to military adoption, they were not in widespread use. Rounds like the 9mm, the 5.56/.223 and the 7.62x39mm are all popular because of military adoption.
Even the .45 ACP would likely not have survived as long as it has were it not for guns like the 1911 pistol and Thompson submachine gun, both of which were adopted by the U.S. military.
So, why are there so many ammo calibers? It’s a long story and a combination of capitalism, necessity, creativity and good old-fashioned innovation.
That’s the beauty of the gun world: There are so many options available to everyone that you can always find something you like.
Plus, once you do find something you like, there’s a very good chance it’s going to hang around for a long time. We’ve said it before, but guns are subjective in a lot of ways, and this just serves to prove that’s true.
There are so many calibers available today, it’s virtually impossible to know what they all are — much less try and shoot them all.
But that shouldn’t stop you from trying.
