Can You Shoot 5.56 In A 223 AR-15?

If you are passionate about firearms, then chances are you have heard of an AR-15 rifle and want to learn more about the ammunition it needs.

Nowadays, there are many gun enthusiasts who treat 223 Remington and 5.56 Nato rounds as the same thing, which can have dangerous consequences when used under the wrong circumstances.

Can You Shoot 5.56 In A 223 AR-15

For while both cartridges are similar, there are some subtle differences that set them apart. 

So if you want to learn more about the differences between these two rounds, then you have come to the right place. 

In this article, we will take a look at 223 and 5.56 rounds, while also determining if you can shoot 5.56 in a 223 AR-15…

223 VS 5.56 Rounds – What’s The Difference? 

If you were to compare a 223 and 5.56 round, you would notice that the two rounds are almost identical, as both bullets have the same external case and dimensions.

Because of this, it is possible to load a 5.56 mm chamber with 223 ammunition and vice versa, which can save both time and effort. 

However, this does not mean that the two rounds are the same, as there are some subtle differences that set them apart. 

For example, 5.56 cases are much thicker than their 223 counterparts, which is a common practice in the special forces.

Because the dimensions of both rounds are almost identical, this also means that the 5.56 cases have less capacity, which can result in higher pressure and combustion.

Comparing the two rounds can also be complicated, as 223 rounds are recognized by the sporting arms and ammunition manufacturers institute, while 5.56 rounds are not.

However, the latter rounds are notable for their higher pressure, which is able to exceed the maximum 55000 psi. 

For this reason, 5.56 firearms are built to withstand increased amounts of pressure, while 223 chambers are not. 

It is also important to note that the dimensions of the chambers also differ, with 223 rounds being smaller in comparison.

These rounds also feature a steeper angle and a shorter leade, which increases the velocity and accuracy of the cartridge. 

5.56 Nato rounds were first produced for the US military and were compatible with various rifles, such as the M-16A1, M-16A2, and the M-4.

However, it is important to remember that the M-16A1 has a slower twist rate, as it was made to be compatible with different weighted bullets. 

Because of its association with the armed forces, the 5.56 Nato round was designed with a longer leade and shallow angle, which helped to increase its performance and velocity.

This also came with the benefit of improving the firearm’s reliability, as you could allow carbon and other materials to build up without impacting the rifle’s functions. 

Since the 5.56 round uses more pressure than its 223 cousins, it can be dangerous when used in a smaller chamber, which brings us to…

Can You Shoot 5.56 In A 223 AR-15 (1)

Can You Shoot 5.56 In A 223 AR-15?

In most instances, 223 ammunition can be fired from a 223 AR-15 rifle, with the same being said of 5.56 ammunition and its respective chamber.

In fact, firing 223 rounds from a 223 chamber and 5.56 rounds from a 5.56 chamber will result in the best overall performance and aim. 

However, it is also possible to shoot 223 Remington rounds from a 5.56 mm chamber, as the bullets are smaller and require less pressure.

That being said, you should never shoot 5.56 rounds from a 223 AR-15 rifle, as something could go wrong and result in a dangerous or fatal incident. 

This means that while it is acceptable to fire 223 rounds from a 5.56 mm chamber, the same cannot be said for the reverse. 

The reason for this is that firing 5.56 rounds from a 223 AR-15 rifle can result in a powerful pressure spike, which could damage the rifle or even make it explode.

If you choose to use this ammunition in the wrong rifle, you will need to be wary of excess pressure, which can take the form of blown or flattened primers. 

How Can You Avoid This? 

If you want to avoid these incidents from happening, then you will need to make sure that you are using the correct ammunition for your AR-15. 

To do this, you must first examine your rifle and determine whether it’s a 223 Remington or a 5.56 Nato. In most cases, this involves taking your rifle and checking the top of the barrel near the muzzle.

The manufacturer can also be located on the receiver or side of the chamber. If the barrel says 223 Remington, then you should be able to tell what kind of rifle you own. 

However, if it says 5.56 mm, this does not necessarily mean that you own a 5.56 Nato that is compatible with all Nato ammunition.

This is because 5.56 mm chambers are rarely made equally and the only way to ensure the correct rounds is by measuring the throat of the chamber yourself.

Until then, we recommend using 223 ammunition to load your rifle, as this is the safer option. 

Once you have determined what AR-15 rifle you own, you can decide what ammunition you want to use.

While we do not recommend using 5.56 rounds in a 223 chamber, it is still a practice used by some shooters.

If you own a 5.56 Nato rifle, then we advise using the correct ammo and 223 rounds as a suitable alternative. 

Final Thoughts 

While it is possible to load a 223 AR-15 rifle with 5.56 ammunition, it is not recommended, as the high pressure could make the firearm explode. 

Instead, you should endeavor to use the correct ammunition for their respective chambers, as this will often yield a more accurate performance.

However, it is possible to use 233 rounds in a 5.56 rifle when you are out of other options. 

Matthew Osborn

Matt is an entrepreneur who has created and successfully exited multiple companies and brands. Now, he dedicates his time to Legionary, where he produces content on guns, family, and freedom.

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