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What is NATO Ammo?

We look at the term NATO ammo, what it means, and how NATO ammo is different from its civilian counterparts.

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By
Aden Tate (Author)

Locksmith. Outdoorsman. Author of 3 books on survival & prepping

Published Nov 8, 2023
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With NATO making regular news headlines recently, you may have found yourself wondering why that word keeps popping up on ammunition boxes at your local gun store.

Just what is NATO ammo?

To answer your question, let’s take a deep dive into the intricacies of NATO ammunition, where it came from, and why it even exists in the first place.

Logistics of War

Imagine you’re an American soldier who has been deployed to the Romanian forests to fight an enemy nation.

As mortar rounds rain down all around you and enemy bullets shatter the trees overhead, you return fire against your enemy. The fight has been going on for 20 minutes now, and there’s no shortage of targets.

US soldiers fighting in the Philippines WW2
U.S. soldiers fight their way through Baleta Pass near Baugio, Luzon, Philippines, sometime in late February 1945. (Photo: US Army)

Unfortunately, you have just run out of ammunition for your battle rifle. There’s a cheeky British chap lying in the scrape next to you. “I need more ammo!” you yell.

But he fires a different type of cartridge than you do.

The two of you are quickly overrun. He’s shot and killed. You spend the next 10 years as a prisoner of war.

This story isn’t a stretch from the truth at all. This is precisely the same position many Allied men found themselves in during World War II.

British and American soldier WW2
A US soldier and a British soldier share a drink over a foxhole.

As French, American, and British men joined together to fight the Nazi powers, they routinely found themselves literally fighting side by side. This led to the above scenario an untold number of times.

It didn’t take long for people to realize that a successful alliance would require standardized equipment.

The Birth of NATO

After World War II, Europe wanted to better protect itself against blitzkrieg-style attacks and the threat of nuclear warfare.

The answer seemed to lay in the forming of an alliance. By 1949, The North Atlantic Treaty Organization was established.

NATO logo
NATO logo. (Source: Wikimedia Commons)

Among the many provisions included with becoming a NATO member was Article 5. This states that an attack on one NATO member is an attack on all NATO members and, therefore, requires all NATO members to defend it.

Seeing that the probability of these soldiers all fighting in the same trenches together was now higher than ever, the concept of standardized equipment was adopted.

The Arms Race

England and America both wanted to be the ones that had the first NATO-approved cartridges.

.280 British vs 7.62x51
.280 British (left) vs 7.62x51mm (right)

As a result, both countries spent a lot of time and money researching new cartridge designs.

England produced the .280 for their EM-2 rifle, while America produced what was, in essence, the 7.62x51mm for their M14.

EM-2 Rifle
British EM-2 rifle.

Enter Winston Churchill.

Though the English cartridge and rifle were better than the American offerings, Churchill realized a few things.

America had just bailed out England in the last war, and he needed America to stay in NATO if England had much of a hope of national defense. He figured that ticking off America by forcing them to choose a British rifle was probably not a good way to start the treaty.

Winston Churchill shooting
Winston Churchill firing an M1 Carbine. (Photo: Wikimedia Commons)

So, Churchill signed a contract to order Belgian FN FALs chambered in the American-made 7.62x51mm cartridge. The round became the first standardized NATO cartridge in 1953. (It wasn’t ratified till 1957, however.)

Canada, Germany, Austria, and the Netherlands soon picked up the FN FAL as well. America ended up going with the M14 — a decision that soon led to another NATO cartridge.

Early FN FAL
An early model FN FAL (Photo: Wikipedia)

Picking a Sidearm

Even with a rifle in hand, a soldier does need a sidearm, as Alvin C. York has demonstrated.

Shortly after the adoption of the 7.62x51mm NATO in 1953, the 9x19mm NATO was adopted in 1955.

SIG-SAUER-M17-9mm-P

It doesn’t appear that there was anywhere near the political wrangling over the choosing of a sidearm caliber as there was over a rifle caliber.

I believe this is due to the understanding that there was a lot more money to be made manufacturing rifles and rifle ammunition than pistols.

Time for an Upgrade

It didn’t take long for America to realize that the M14 wasn’t the best weapon design.

M14 in Vietnam
An M14 being used early in the Vietnam War.

Aside from its significant recoil compared to other battle rifles, the 7.62x51mm NATO cartridge was also relatively heavy.

After the US military conducted a study showing that an 8-man team carrying an M16, which fired 5.56x45mm ammunition, had the same firepower as an 11-man team using M14s, the case was well-made that it was time for a new round.

5.56 vs 7.62x51
5.56x45mm (left) vs 7.62x51mm (right)

NATO was on board with this new round and its ability to be a force multiplier. In 1977, they adopted the 5.56x45mm NATO as a standardized cartridge. (It wasn’t ratified until 1981)

Vietnam

A major catalyst for the adoption of the 5.56x45mm NATO was the Vietnam War. The U.S. had largely switched to 5.56 during the events of the Vietnam War.

M16 Vietnam
A soldier utilizing an M16 during Vietnam.

In the following years, America also maintained a large military presence in Europe throughout the Cold War.

As Europeans looked around at all of these American soldiers with M16s loaded with 5.56x45mm NATO, they realized that it was in their best interest to use the same ammunition.

How NATO Chooses Standardized Ammunition

There are two steps that a new cartridge or gun must pass if it wants to meet NATO qualifications.

First, it has to pass the Multi-Caliber Manual of Proof and Inspection (M-C MOPI)/the Manual of Proof and Inspections (MOPI). Secondly, it has to pass the NATO-drafted standardization agreements (STANAGs).

Faxon Firearms Ascent AR-15 Various Mags
Ever wonder why those aluminum AR-15 mags are called STANAG mags? Now you know!

If it can pass both of these rather strenuous phases, the ammunition will be “NATO Qualified,” meaning that NATO highly recommends its use for NATO Nominated Weapons (NNWs).

The catch here is that NATO members don’t technically have to make the same type of ammunition as one another — It’s just recommended. For example, in the past, there have been significant differences between American-made 5.56x45mm NATO and British-made 5.56x45mm NATO. 

British L2A2 ammo
British L2A2 5.56 ammunition. (Photo: Rifleshooter)

At one point during the Global War on Terror, Lake City Army Ammunition Plant wasn’t able to produce enough ammunition for US soldiers overseas. Because of this, the US ended up getting a lot of British-made L2A2 5.56 ammo shipped in.

Wisely, the L2A2 was used for training only rather than combat. This was good, as the ammo caused a host of malfunction issues that hindered training. The 82nd Airborne, in particular, had numerous feeding issues.

While NATO does standardize arms and armament, there is still enough variance to cause significant issues in the event munitions are shared.

Not exactly the same gif

Are There Differences Between NATO Ammo and Civilian Variants?

Ah, the age-old questions. “Can I shoot 5.56x45mm in my .223?” “What about 7.62x51mm in my .308?”

As expected, there are differences between the two cartridges. While the dimensions of the NATO and civilian cartridges are virtually the same, the innards (the projectile, powder, etc.) are different.

Deconstructed 7.62x51 Round
Deconstructed 7.62x51 Round

If you want to know more, I recommend checking out our articles on the subject of .223 vs 5.56, and 9mm Luger vs 9mm Parabellum.

What is the Future of NATO Ammunition?

Personally, I don’t think we’re too far away from seeing the US Army’s new 6.8mm ammunition becoming the standard caliber.

SIG Sauer MCX Spear shoot Bog Hunt
The Sig MCX Spear, a civilian variant of the Army's new XM5 rifle.

America is too big a part of the organization for Europe not to take heed that we are moving away from the 5.56x45mm NATO. Just like during the Cold War, if more and more American soldiers carry different ammunition, they would be wise to consider switching as well.

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Final Thoughts

While the process for choosing new NATO Qualified gear is intensive, NATO ammunition has consistently stuck around for a long time after being selected.

Consider the spread of 9x19mm NATO, 5.56x45mm NATO, and 7.62x51mm NATO — three of the most popular calibers in gun stores and homes throughout America.

5.56 vs 9mm vs 7.62x51
Projectiles from a 5.56x45mm (left), 9x19 (center), and a 7.62x51mm (right)

If you were wondering what NATO ammo actually is, hopefully we’ve helped provide some answers.

What are your thoughts on all of this? Let us know in the comment section below! Interested in a good ol' fashioned caliber shootout? Check out our article on 7.62 vs 5.56 NATO!

Aden Tate

Written By
Aden Tate
Author

Aden Tate is a writer and locksmith in The Beautiful South. When he’s not hammering away at a keyboard, he can be found raising goats, pigs, bees, chickens, mushrooms, and crops.

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