How Is Ammunition Named?

How is Ammo Named?
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How Is Ammunition Named?

For many types of ammunition, the name is simply the caliber of the gun being used.

It’s pretty common to hear exchanges such as “Hey, how much 9mm do you have?” Or, “I’m getting low on 45.”

But why do we do that?

Just in those previous examples, there was information left out, even without going into the full name of the ammunition.

If we’re being honest, the 9mm should at least have been referred to as 9mm Parabellum and the .45 should’ve at least been called .45 ACP.

And that’s still not entirely the accurate names for those rounds.

Historical Naming of Ammunition

In times past, from the early stages of gun manufacture through the black powder Wild West times, ammunition was often referred to by the caliber of the round and the amount of powder propelling that round.

In those days, the names were actually quite descriptive. You would tell someone the bore of the gun that you were firing and how much powder you used to do it.

So, for example, you might end up with a round named something like 45–70.

This informs someone that you were shooting a 45-caliber projectile that was being propelled out of the firearm by 70 grains of powder.

This was an especially common practice during the days of black powder.

Manufacturers and Ammo Names

As time went on, manufacturers began to mass produce these rounds and standardize their production.

At that point, the addition of the manufacturer's name to the round became commonplace.

With this practice, you might now have a round named something like 40-60 Marlin or 45-70 Remington. Sounds good, right?

Unfortunately, this actually began to muddy the waters a bit.

Manufacturers might end up having rounds that sounded similar but were completely different and incompatible with each other. And you could also have rounds that had different numbers but were actually compatible. 

For example, a gun that fired the aforementioned 40-60 Marlin was capable of firing the 40-65 Winchester but not the 40-60 Winchester. Confused?

Yeah, imagine trying to sort it all out back when it was happening.

Now that these rounds were being manufactured and the gun owners were purchasing them rather than making them themselves, this confusion became a real problem. 

Smokeless Powders Add More Confusion

Interestingly enough, the addition of smokeless powders and the market shift away from black powder only served to compound the confusion.

The existing name for any given round couldn’t be transferred over because it was based on the amount of powder in round (which, of course, had now changed).

With smokeless powders, the manufacturer mixes might be proprietary and use a different mix than what might’ve been used with black powder.

Plus, simply adding more powder didn't necessarily increase the power of the round in the same way as it did with black powder.

So now, thanks to the new manufacturing processes and the various powders in use, the second number became largely irrelevant.

There was no longer any point in putting the amount of powder the round contained because it could vary by manufacturer without having any real impact on the standardization of the round itself.

British Ammo Naming System 

In typical fashion, the British system was very similar to the American system — well, except it's the complete opposite.

Sounds about right for how we all tend to operate. We drive on the right side of the road; they drive on the left.

We sit on the left side of the car; they sit on the right. Their ammunition naming system is no different.

The British System eliminated the powder and grain weight.

They would do caliber as we did, but they also used the parent cartridge that the round was derived from.

Also, they flipped it in reverse and put the caliber last. Therefore, a British .45 caliber round that was derived from a 577 cartridge would be a 577-450.

Then, to spruce things up a bit, they threw in “express” to indicate a higher speed round. Completely lost yet?

Year Numbering in Ammo Names

Around the time of transition away from black powder, another habit began forming with the naming of rounds.

It was the addition of the year the round was adopted. While it didn’t happen with a lot of rounds, it did happen with some popular cartridges, such as the 30-06.

From looking at that name, if you didn’t know any better, you would think that this was a 30 caliber round powered by six grains of powder.

You can see the problem that would arise from that. Six grains of powder doesn’t make much sense to anyone who’s been around firearms for a while. But that’s not what the 30-06 represented.

It was named as a 30 caliber round adopted by the military in 1906.


By this point, things were really mixed up and all over the place. There were no standards for naming the rounds and nothing to create some kind of recognizable consistency.

In fact, it got so bad that the federal government finally decided there needed to be something done to fix it.

Enter SAAMI — the Sporting Arms and Ammunition Manufacturers’ Institute.

Created in 1926, SAAMI was established by the U.S. federal government and tasked with creating and publishing industry standards for safety, interchangeability, reliability and quality, coordinating technical data and promoting safe and responsible firearms use.

Part of that included creating and maintaining standards for terminology.

Interestingly, SAAMI doesn’t actually regulate naming or anything like that.

But the act of coordinating and logging names has helped to mitigate the confusion to a degree.

According to SAAMI, the naming of rounds is largely a market function as long as it doesn’t interfere with safe usage.

Basically, SAAMI ensures that what you call the cartridge doesn’t lead to unsafe usage of it.

How Ammunition Is Named

Thanks to efforts related to standardization and ensuring safety, manufacturers now name ammunition based on specific factors.

The names of the ammunition are created based on marketing their performance. Ammunition is labeled based on caliber, style and grain weight.

So, when we look at the label, we see the full name of the ammunition, which would be something like 9 x 19 mm Parabellum 147 grain jacketed hollow point (JHP).

We’ve almost come full circle. Nowadays, rounds are named to indicate their caliber size and how they perform.

Ironically, this is very similar to the old black powder days of caliber and powder.

This is why we tend to, in conversation, refer to them simply by the caliber, since all types of ammo are labeled based on the caliber and then give an additional identifier based on their intended performance.

So, we’ll simply say 9mm instead of saying 9x19mm parabellum jacketed hollow point.

Or, we might say something like “I’ve got some .45 target ammo” instead of saying that we have .45 ACP ball ammunition. 

So, in reality, how is ammunition named? Well, we — the gun users — name it.

We look at it, assess what it is and what it does, and then refer to it in the simplest ways we know how.

That’s how we go from seeing a box labeled .40 caliber Smith and Wesson premium 180 grain Jacketed Hollow Point to calling it simply .40 cal.

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This subject sat on the fence as boring and interesting. The writing on it was really good, and the conclusion for me is that it was interesting on a some what boring subject. HA! It was also very informative so I am walking away with some new knowledge, so that you for that! The images are super cool. The changes in ammo saw that the gunpowder horn was put out of use, but I am glad that they still could use it as a drinking horn!